#include <stdio.h>
#include <string.h>
#include <iostream>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <map>
#include <string>
#include <algorithm>
#include <numeric>
#include <utility>
#include <cmath>

using namespace std;

typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;

const int iinf = 1 << 29;
const long long linf = 1ll << 61;

#define dump(x) cerr << #x << " : " << x << '\n'
#define MOD(x, y) (((y) + (x) % (y)) % (y))

int M, N;
int a[8][8];
int b[8][8];

void flip(int y, int x) {
	int dx[] = { 0, 1, 1, 0, -1, -1, -1, 0, 1 };
	int dy[] = { 0, 0, 1, 1, 1, 0, -1, -1, -1 };
	for (int i = 0; i < 9; i++) {
		int X = x + dx[i];
		int Y = y + dy[i];
		if (X < 0 || X >= N || Y < 0 || Y >= M) continue;
		b[Y][X] = 1 - b[Y][X];
	}
}

int main(int argc, char* argv[])
{
	scanf("%d%d", &M, &N);
	for (int i = 0; i < M; i++) {
		for (int j = 0; j < N; j++) {
			scanf("%d", &a[i][j]);
		}
	}
	int ans = iinf;
	for (int i = 0; i < (1 << 8); i++) {
		for (int j = 0; j < (1 << 8); j++) {
			int count = 0;
			if ((i & 1) != (j & 1)) continue;
			memcpy(b, a, sizeof(a));
			for (int x = 0; x < N; x++) {
				if ((i >> x) & 1) {
					flip(0, x);
					count++;
				}
			}
			for (int y = 1; y < M; y++) {
				if ((j >> y) & 1) {
					flip(y, 0);
					count++;
				}
			}
			for (int y = 1; y < M; y++) {
				for (int x = 1; x < N; x++) {
					if (b[y - 1][x - 1] == 1) {
						flip(y, x);
						count++;
					}
				}
			}
			bool flag = true;
			for (int x = 0; x < N; x++) {
				if (b[M - 1][x] == 1) flag = false;
			}
			for (int y = 0; y < M; y++) {
				if (b[y][N - 1] == 1) flag = false;
			}
			if (flag) {
				ans = min(ans, count);
			}
		}
	}
	if (ans <= M * N) {
		printf("%d\n", ans);
	} else {
		printf("Impossible\n");
	}

	return 0;
}