/*
ID: espr1t
LANG: C++
TASK: Demo
CONTEST: CodeIT, Round 2, 2011
KEYWORDS: 
*/

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <vector>
#include <algorithm>
#include <cstdlib>
#include <string>
#include <queue>
#include <map>
#include <set>
#include <ctime>

#define MAX 1024

using namespace std;
FILE *in; FILE *out;

int n, m, k, h;
int a[MAX][MAX], parity[MAX];
int cols[MAX];

inline int popcount(unsigned long long mask)
{
	int ans = 0;
	while (mask) {ans++; mask &= (mask - 1);}
	return ans;
}

int cntt = 0;
vector < pair <unsigned long long, unsigned long long> > q, q1, q2;

void recurse(int idx, int midx, int rem, unsigned long long mask, unsigned long long used)
{
	if (idx >= midx)
	{
		q.push_back(make_pair(mask, used));
		return;
	}
	// Don't use
	recurse(idx + 1, midx, rem, mask, used);

	// Use
	if (rem > 0)
	{
		unsigned long long nmask = mask;
		for (int i = 0; i < n; i++) if (a[i][cols[idx]])
			nmask ^= ((unsigned long long)1 << i);
		recurse(idx + 1, midx, rem - 1, nmask, used | ((unsigned long long)1 << cols[idx]));
	}
}

void makeClean(vector < pair <unsigned long long, unsigned long long> >& q,
			   vector < pair <unsigned long long, unsigned long long> >& at)
{
	if (q.empty()) return;
	else sort(q.begin(), q.end());

	unsigned long long last = q[0].first;
	at.push_back(q[0]);
	for (int i = 1; i < (int)q.size(); i++)
	{
		if (q[i].first != last)
		{
			last = q[i].first;
			at.push_back(q[i]);
		}
		else
		{
			if (popcount(at.back().second) > popcount(q[i].second))
				at.back().second = q[i].second;
		}
	}
}

int bsearch(vector < pair <unsigned long long, unsigned long long> >& v, unsigned long long val)
{
	int left = 0, right = (int)v.size() - 1;
	while (left <= right)
	{
		int mid = (left + right) / 2;
		if (v[mid].first == val) return mid;
		if (v[mid].first < val) left = mid + 1;
		else right = mid - 1;
	}
	return -1;
}

int main(void)
{
	in = stdin; out = stdout;
	in = fopen("bits.in", "rt"); out = fopen("bits.out", "wt");
	
//	unsigned sTime = clock();
	fscanf(in, "%d %d", &n, &k);
	
	char buff[MAX];
	for (int i = 0; i < n; i++)
	{
		fscanf(in, "%s %d", buff, &parity[i]);
		m = (int)strlen(buff);
		for (int c = 0; c < m; c++) a[i][c] = buff[c] - '0';
	}
	
	unsigned long long mask = 0;
	for (int i = 0; i < n; i++) if (parity[i])
		mask |= ((unsigned long long)1 << i);

	for (int i = 0; i < m; i++)
		cols[i] = i;
	random_shuffle(cols, cols + m);

	h = m / 2;
	recurse(0, h, min(8, k), 0, 0);
//	fprintf(stderr, "Execution time here is %.3lf\n", (double)(clock() - sTime) / CLOCKS_PER_SEC);
	makeClean(q, q1); q.clear();
//	fprintf(stderr, "Execution time here is %.3lf\n", (double)(clock() - sTime) / CLOCKS_PER_SEC);
	recurse(h, m, min(8, k), 0, 0);
//	fprintf(stderr, "Execution time here is %.3lf\n", (double)(clock() - sTime) / CLOCKS_PER_SEC);
	makeClean(q, q2); q.clear();
//	fprintf(stderr, "Execution time here is %.3lf\n", (double)(clock() - sTime) / CLOCKS_PER_SEC);
	

	int ans = -1;
	unsigned long long ansMask = 0;

	for (int i = 0; i < (int)q1.size(); i++)
	{
		int cnt = popcount(q1[i].second);
		unsigned long long nmask = mask ^ q1[i].first;
		
		int idx = bsearch(q2, nmask);
		if (idx != -1)
		{
			int ocnt = popcount(q2[idx].second);
			if (cnt + ocnt <= k && ans < cnt + ocnt)
			{
				ans = cnt + ocnt;
				ansMask = q1[i].second | q2[idx].second;
				if (ans == k) break;
			}
		}
	}

	fprintf(out, "%d\n", ans);
	vector <int> v;
	for (int i = 0; i < n; i++)
		if (ansMask & ((unsigned long long)1 << i)) v.push_back(i);
	for (int i = 0; i < (int)v.size(); i++)
		fprintf(out, "%d%c", v[i], i + 1 == (int)v.size() ? '\n' : ' ');
	
	return 0;
}