#include<cstdio>
#include<vector>
#include<algorithm>
#include<functional>
#include<cmath>
#include<ctime>

using namespace std;

int N, M, B, K, NN, max_res, res[1001], s[1001][1001], tab_and[1001];
int tem[1001], e[1001];
int timer;

struct statis {
	int n, sum;
	bool operator < (const statis &a) const { return (this->sum < a.sum); }
}st[1001];


void Input() {
	int a, b;
	FILE*in = fopen("subsetselection.in", "r");
	fscanf(in, "%i %i %i\n", &N, &M, &B);
	for (int i = 1; i <= N; i++) {
		for (int j = 1; j <= M; j++) {
			fscanf(in, "%i \n", &s[i][j]);
		}
		fscanf(in, "\n");
	}
}

bool Timer(){ return clock() / (double)CLOCKS_PER_SEC > 4.8; }


void MinSum() {
	for (int i = 1; i <= N; i++){
		st[i].n = i;
		for (int j = 1; j <= M; j++) {
			st[i].sum += s[i][j];
		}
	}
	sort(&st[1], &st[N + 1]);
	for (int i = 1; i <= N; i++) {
		e[i] = st[i].n;
	}
}

void Solve() {
	int c, cc, a, sum = 0, tsum, vsum;
	tab_and[1] = 1;
	for (int i = 2; i <= N; i++) {
		tab_and[i] = tab_and[i - 1] * 2;          
	}
	cc = (int)pow(2, N) - 1;                  
	for (int c = 1; c <= cc; c++) {                              
		tsum = 0;
		for (int j = 1; j <= M; j++) {
			vsum = 0;
			for (int i = 1; i <= N; i++) {
				if ((c & tab_and[i]) == 0)continue;
				vsum += s[i][j];
			}
			a = vsum % B; tsum += a*a;                 
		}                                        
		if (tsum > sum) { sum = tsum; max_res = c; }
	}
	a = 1;
	for (int i = 1; i <= N; i++) {
		if ((max_res & tab_and[i]) > 0) { K++; res[a] = i; a++;}
	}                                           
}


void Solve5(int NN) {
	MinSum();
	int c, cc, a, sum = 0, tsum, vsum;
	tab_and[1] = 1;
	for (int i = 2; i <= NN; i++) {
		tab_and[i] = tab_and[i - 1] * 2;
	}
	cc = (int)pow(2, NN) - 1;
	for (int c = 1; c <= cc; c++) {
		tsum = 0;
		for (int j = 1; j <= M; j++) {
			vsum = 0;
			for (int i = 1; i <= NN; i++) {
				if ((c & tab_and[i]) == 0)continue;
				vsum += s[e[i]][j];                  
			}
			a = vsum % B; tsum += a*a;
		}
		if (tsum > sum) { sum = tsum; max_res = c; }
		if (Timer()) break;
	}
	a = 1;
	for (int i = 1; i <= NN; i++) {
		if ((max_res & tab_and[i]) > 0) { K++; res[a] = st[i].n; a++; }
	}
}

void Solve7() {
	MinSum();
	int c, cc, a, sum = 0, tsum, vsum, NN = 17;
	tab_and[1] = 1;
	for (int i = 2; i <= NN; i++) {
		tab_and[i] = tab_and[i - 1] * 2;
	}
	cc = (int)pow(2, NN) - 1;
	for (int c = 1; c <= cc; c++) {
		tsum = 0;
		for (int j = 1; j <= M; j++) {
			vsum = 0;
			for (int i = 1; i <= NN; i++) {
				if ((c & tab_and[i]) == 0)continue;
				vsum += s[e[i]][j];
			}
			a = vsum % B; tsum += a*a;
		}
		if (tsum > sum) { sum = tsum; max_res = c; }
		if (Timer()) break;
	}
	a = 1;
	for (int i = 1; i <= NN; i++) {
		if ((max_res & tab_and[i]) > 0) { K++; res[a] = st[i].n; a++; }
	}
}

void Output() {
	FILE *out = fopen("subsetselection.out", "w");
	fprintf(out, "%i\n", K);
	for (int i = 1; i <= K; i++) {
		fprintf(out, "%i\n", res[i]);
	}
}


int main() {
	Input();
	if (N <= 20) { Solve(); Output(); return 0; }
	if (N <= 200) { Solve5(19); Output(); return 0; }
	
	Solve7();
	
	Output();

	return 0;
}