#include <iostream>
#include <cstdio>
#include <string>
#include <utility>
#include <algorithm>
#include <stdlib.h>
#include <math.h>
#include <vector>
#include <time.h>
#include <iterator>
/*#include <stdio.h>
#include <sstream>*/


using namespace std;
FILE* in; FILE* out;
//const int BITS=64 000 000;
const clock_t TIME_LIMIT = (clock_t) (4.7* CLOCKS_PER_SEC);
const clock_t HARD_LIMIT = (clock_t) (4.95* CLOCKS_PER_SEC);
clock_t BEGIN_TIME;
int N,M,B;
vector<unsigned short int>FindResult(vector<unsigned short int> a1,vector<unsigned short int> a2)
{
    vector<unsigned short int>result;
    for(int j=0;j<M;j++){
        result.push_back((a1[j]+a2[j])%B);
    }
    return result;
}
int CalcResult(vector<unsigned short int>a)
{
    int result=0;
    for(int j=0;j<M;j++)
        result+=a[j]*a[j];
    return result;
}
int memory;
vector<unsigned short int>ans;
int mxRes=0;
vector<vector<unsigned short int> >results;
vector<vector<unsigned short int> >arr;
vector< vector <unsigned short int> >FindComb(unsigned short int n,unsigned short int k)
{
    vector< vector <unsigned short int> > nil;
    if(results.size()>memory)return nil;
    if(clock()-BEGIN_TIME>TIME_LIMIT)return nil;
    if(k==1)
    {
        vector< vector <unsigned short int> > nil;
        results.clear();
        for(unsigned short int i=0;i<n;i++)
        {
            vector<unsigned short int>toInsert(1,i);
            //toInsert.push_back(i);
            int currRes=CalcResult(arr[i]);
            if(mxRes<currRes)
            {
            mxRes=currRes;
            ans=toInsert;
            }
            nil.push_back(toInsert);
            results.push_back(arr[i]);
        }
        return nil;
    }

    vector< vector <unsigned short int> >prev=FindComb(n,k-1);
    vector< vector <unsigned short int> >curr;
    vector<vector<unsigned short int> >newresults;
    for(int i=prev.size()-1;i>=0;i--)
    {
        if(mxRes==M*(B-1)*(B-1))break;
        int last=prev[i].back();
        vector<unsigned short int>popped_r;
        popped_r=results[i];
        vector<unsigned short int>popped_p;
        popped_p=prev[i];
        for (int j=last+1;j<n;j++)
        {
        vector<unsigned short int> cresult=FindResult(popped_r,arr[j]);
        vector<unsigned short int>toInsert;
        toInsert=popped_p;
        toInsert.push_back(j);
        int currRes=CalcResult(cresult);
        if(currRes>mxRes)
        {
            mxRes=currRes;
            ans=toInsert;
        }
        if(mxRes==M*(B-1)*(B-1))break;
        curr.push_back(toInsert);
        newresults.push_back(cresult);
        if(newresults.size()>memory)break;
        if(clock()-BEGIN_TIME>TIME_LIMIT)break;
        }
        if(newresults.size()>memory)break;
        if(clock()-BEGIN_TIME>TIME_LIMIT)break;
    }
results=newresults;
return curr;
}

vector< vector <unsigned short int> >FindComb1(unsigned short int n,unsigned short int k)
{
    if(k==1)
    {
        vector< vector <unsigned short int> > nil;
        results.clear();
        for(int i=0;i<n;i++)
        {
            vector<unsigned short int>toInsert;
            toInsert.push_back(i);
            int currRes=CalcResult(arr[i]);
            if(mxRes<currRes)
            {
            mxRes=currRes;
            ans=toInsert;
            }
            nil.push_back(toInsert);
            results.push_back(arr[i]);
            //memory-=M;
        }
        return nil;
    }
    vector< vector <unsigned short int> > nil;
    if(results.size()>memory)return nil;
    if(clock()-BEGIN_TIME>TIME_LIMIT)return nil;
    vector< vector <unsigned short int> >prev=FindComb(n,k-1);
    vector< vector <unsigned short int> >curr;
    for(int i=prev.size()-1;i>=0;i--)
    {
        if(mxRes==M*(B-1)*(B-1))break;
        int last=prev[i].back();
        vector<unsigned short int>popped_r;
        if(N>200)
        {
        popped_r=results.back();
        results.pop_back();
        }
        else popped_r=results[i];
        vector<unsigned short int>popped_p;
        if(N>200)
        {
        popped_p=prev.back();
        prev.pop_back();
        }
        else popped_p=prev[i];
        for (int j=last+1;j<n;j++)
        {
        vector<unsigned short int> cresult=FindResult(popped_r,arr[j]);
        vector<unsigned short int>toInsert;
        toInsert=popped_p;
        toInsert.push_back(j);
        int currRes=CalcResult(cresult);
        if(currRes>mxRes)
        {
            mxRes=currRes;
            ans=toInsert;
        }
        if(mxRes==M*(B-1)*(B-1))break;
        curr.push_back(toInsert);
        if(clock()-BEGIN_TIME>TIME_LIMIT)break;
        }
        if(clock()-BEGIN_TIME>TIME_LIMIT)break;
    }
return curr;
}

int main(){
    in = stdin; out = stdout;
    in = fopen("subsetselection.in", "rt"); out = fopen("subsetselection.out", "wt");
BEGIN_TIME = clock();
fscanf(in, "%d%d%d", &N,&M,&B);
//memory=BITS-N*M;
for(int i=0;i<N;i++){
    vector<unsigned short int>curr;
    for(int j=0;j<M;j++)
    {
        int c;
        fscanf(in, "%d", &c);
        if(c==B)c=0;
        curr.push_back(c);
    }
    arr.push_back(curr);
}
vector<vector<unsigned short int> > combinations;
if(N<201)
{
memory=290000;
combinations=FindComb(N,N);
}
//else if(N<201)FindComb(N,3);
else
{
memory=62000;
FindComb1(N,2);
}

fprintf(out, "%d\n", ans.size());
for(int i=0;i<ans.size();i++)fprintf(out, "%d\n", ans[i]+1);
return(0);
}