#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>
#include <cstdlib>
#include <time.h>
using namespace std;

const double TL = 4.5;

bool TimeIsOK()
{
    return (double)clock() / (double)CLOCKS_PER_SEC < TL;
}

int n,m,b;
int nums[1011][1011];

int maxVal = 0;
vector<int> bestChoice;

int val = 0;
vector<int> choice;

int current[1011];

void optimal()
{
    int i,j,in;

    for (i=0;i<(1<<n);i++)
    {
        for (j=1;j<=m;j++)
        {
            current[j] = 0;
        }
        choice.clear();

        for (j=1;j<=n;j++)
        {
            if ( (i&(1<<(j-1))) > 0 )
            {
                choice.push_back(j);
                for (in=1;in<=m;in++)
                {
                    current[in] += nums[j][in];
                }
            }
        }

        val = 0;
        for (j=1;j<=m;j++)
        {
            current[j] %= b;

            val += current[j] * current[j];
        }

        if (val > maxVal)
        {
            bestChoice = choice;
            maxVal = val;
        }
    }

    printf("%d\n",(int)bestChoice.size());

    for (i=0;i<bestChoice.size();i++)
    {
        printf("%d\n",bestChoice[i]);
    }

    fprintf(stderr,"Score = %d\n",maxVal);

    return;
}

int ids[1011];
int modb[1011];

bool active[1011];

int main()
{
    freopen("subsetselection.in","r",stdin);
    freopen("subsetselection.out","w",stdout);

    srand(1);

    int i,j;
    int iterations = 0;

    scanf("%d %d %d",&n,&m,&b);

    for (i=0;i<=3*b;i++)
    {
        modb[i] = i % b;
    }

    for (i=1;i<=n;i++)
    {
        ids[i] = i;

        for (j=1;j<=m;j++)
        {
            scanf("%d",&nums[i][j]);
            nums[i][j] %= b;
        }
    }

    if (n <= 20 && m <= 20)
    {
        optimal();
        return 0;
    }

    for (i=1;i<=m;i++)
    {
        current[i] = 0;
    }

    for (i=1;i<=n;i++)
    {
        active[i] = false;
    }

    while(TimeIsOK())
    {
        iterations++;

        int k = rand() % n + 1;

        val = 0;
        if (active[k])
        {
            for (i=1;i<=m;i++)
            {
                current[i] = modb[ current[i] - nums[k][i] + b ];
                val += current[i] * current[i];
            }
        }
        else
        {
            for (i=1;i<=m;i++)
            {
                current[i] = modb[ current[i] + nums[k][i] ];
                val += current[i] * current[i];
            }
        }

        active[k] = !active[k];

        if (val > maxVal)
        {
            bestChoice.clear();
            maxVal = val;

            for (i=1;i<=n;i++)
            {
                if (active[i])
                {
                    bestChoice.push_back(i);
                }
            }
        }
    }

    printf("%d\n",(int)bestChoice.size());

    for (i=0;i<bestChoice.size();i++)
    {
        printf("%d\n",bestChoice[i]);
    }

    fprintf(stderr,"Score = %d\n",maxVal);
    fprintf(stderr,"Total iterations = %d\n",iterations);

    return 0;
}