#include <iostream>
#include <vector>
#include <stack>
#include <unordered_set>
#include <numeric>
#include <iterator>
#include <unordered_map>
#include <array>
#include <map>
#include <cstring>
#include <iomanip>
#include <string>
#include <algorithm>
#include <cmath>
#include <ctgmath>
#include <set>
#include <queue>
#include <fstream>
#include <ostream>
#include <random>
#include <chrono>

using namespace std;
int calcVal(vector<int> all)
{
	int res = 0;
	for (auto i : all)
	{
		res += (i*i);
	}
	return res;
}

void print(int id)
{
	ofstream myfile2;
	myfile2.open("subsetselection.out");
	myfile2 << __builtin_popcount(id) << "\n";
	int cnt = 1;
	while (id > 0)
	{
		if (id & 1)
		{
			myfile2 << cnt << "\n";
		}
		id /= 2;
		cnt++;
	}
}

int main()
{
	int n, m, b;
	ifstream myfile;
	myfile.open("subsetselection.in");
	myfile >> n >> m >> b;

	vector<vector<int>> all(n);
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < m; j++)
		{
			int x;
			myfile >> x;
			all[i].push_back(x);
		}
	}

	int maxi = 0;
	int id = 0;
	for (int i = 0; i <= (1 << (n)); i++)
	{
		vector<int> res(n);
		for (int j = 0; j < n; j++)
		{
			if (i & (1 << j))
			{
				int curr = 0;
				for (int k = 0; k < m; k++)
				{
					res[k] += all[j][k];
					res[k] %= b;
				}
			}
		}
		int val = calcVal(res);
		if (val > maxi)
		{
			maxi = val;
			id = i;
		}
	}
	print(id);
}