#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> PII;

#define fir first
#define sec second
#define ep emplace
#define eb emplace_back

#define lowbit(x) ((x) & (-(x)))

inline int read() {
	int x = 0, f = 1; char ch = getchar();
	for (; !isdigit(ch); ch = getchar()) if (ch == '-') f = -1;
	for (; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + (ch ^ 48);
	return x * f;
}

const int N = 2010;

int n, m;
bitset<N> a[N], b[N];
char s[N];

bool check(int m) {
	for (int i = 1; i <= m; i ++ ) a[i] = b[i];
	int r = 1, t = 1;
	for (int c = 1; c <= min(n, m); c ++ , t = r) {
		for (int i = t; i <= m; i ++ ) if (a[i][c]) t = i;
		if (!a[t][c]) return false;
		swap(a[r], a[t]);
		for (int i = 1; i <= m; i ++ ) {
			if (i == r || !a[i][c]) continue;
			a[i] ^= a[r];
		}
		r ++ ;
	}
	return true;
}

int main() {
	n = read(), m = read();
	for (int i = 1; i <= m; i ++ ) {
		scanf("%s", s + 1);
		for (int j = 1; j <= n; j ++ ) b[i][j] = s[j] ^ '0';
		scanf("%s", s + 1);
		b[i][n + 1] = s[1] ^ '0';
	}
	int l = 1, r = m, ans = -1;
	while (l <= r) {
		int mid = (l + r) >> 1;
		if (check(mid)) r = mid - 1, ans = mid;
		else l = mid + 1;
	}
	if (ans == -1) return puts("Cannot Determine"), 0;
	printf("%d\n", ans), check(ans);
	for (int i = 1; i <= n; i ++ ) {
		if (a[i][n + 1]) puts("?y7M#");
		else puts("Earth");
	}
	return 0;
}