#include <fstream>
// #include <iostream>
#include <ctime>
#include <cstdlib>
#include <cstring>
#include <algorithm>

using namespace std;

unsigned int n, m, k, bestp = 0, currentp, ch, c;
unsigned short a[1000][1000], b, currenta[1000], idx[1000];
bool bestk[1000], currentk[1000];

clock_t start;
const clock_t TC = 4.95 * CLOCKS_PER_SEC;

int main()
{
	start = clock();
	ifstream inp;
	inp.open("subsetselection.in");
	inp >> n >> m >> b;
	for(unsigned int i = 0; i < n; ++i)
	{
		for(unsigned int j = 0; j < m; ++j)
		{
			inp >> a[i][j];
		}
		idx[i] = i;
	}
	inp.close();
	
	for(unsigned i = 0; i < n; ++i)
	{
		for(unsigned int j = 0; j < m; ++j)
		{
			currenta[j] += a[i][j];
			currenta[j] %= b;
		}
	}
	for(unsigned int j = 0; j < m; ++j)
	{
		bestp += currenta[j]*currenta[j];
	}
	// cout << "BESTALL: p=" << bestp << "; ";
	
	memset(bestk, 0, n);
	while(clock() - start <= TC)
	{
		memset(currentk, 0, n);
		memset(currenta, 0, m*(sizeof(unsigned short)));
		random_shuffle(idx, idx+n);
		/*
		cout << "idc: ";
		for(unsigned i = 0; i < n; ++i)
		{
			cout << idx[i]+1 << " ";
		}
		cout << ";" << endl;
		*/
		for(unsigned j = 0; j < n-1; ++j)
		{
			currentk[idx[j]] = true;
			currentp = 0;
			for(unsigned int i = 0; i < m; ++i)
			{
				currenta[i] += a[idx[j]][i];
				currenta[i] %= b;
				// cout << currenta[i] << " ";
				currentp += currenta[i]*currenta[i];
			}
			// cout << "p=" << currentp << endl;
			if(currentp > bestp)
			{
				/*
				cout << "BEST: p=" << currentp << "; ";
				for(unsigned i = 0; i < n; ++i)
				{
					cout << currentk[i] << " ";
				}
				cout << endl;
				*/
				bestp = currentp;
				memcpy(bestk, currentk, n);
				k = j+1;
			}
		}
	}
	
	ofstream out;
	out.open("subsetselection.out");
	// out << "k=";
	out << k << '\n';
	for(unsigned i = 0; i < n; ++i)
	{
		if(bestk[i])
		{
			// out << "i=";
			out << i+1 << '\n';
		}
	}
	out.close();
	// cout << clock() - start << endl;
	return 0;
}