#include <stdio.h>

char line[1 << 10];
int x[1 << 10][1 << 10], now[1 << 10];

int minChanges(int N)
{

}

int main()
{
	int i, j, test, Q, N, M;

	freopen("data.in", "r", stdin);
	freopen("data.out", "w", stdout);

	scanf("%d", &Q);
	for (test = 1; test <= Q; test ++)
	{
		scanf("%d%d", &N, &M);
		for (i = 1; i <= N; i ++)
		{
			gets(x + 1);
			for (j = 1; j <= M; j ++)
				x[i][j] = line[j] - '0';
		}

		memset(now, 0, sizeof(now));
		for (i = 1; i <= N; i ++)
			for (j = 1; j <= M; j ++)
				now[i] += x[i][j];
		int sol = minChanges(N);
		if (sol == -1)
		{
			printf("Case %d: impossible\n", test);
			continue;
		}
		memset(now, 0, sizeof(now));
		for (j = 1; j <= M; j ++)
			for (i = 1; i <= N; i ++)
				now[j] += x[i][j];
		int sol2 = minChanges(M);
		if (sol2 == -1)
		{
			printf("Case %d: row %d\n", test, sol);
			continue;
		}
		printf("Case %d: both %d\n", test, sol + sol2);
	}

	return 0;
}