#include "bits/stdc++.h"

using namespace std;

using ll = long long int;
using ld = long double;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<double, double>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vd = vector<double>;
using vvd = vector<vd>;
using vs = vector<string>;
using vb = vector<bool>;
using vvb = vector<vb>;

const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { -1, 0, 1, 0 };

int gcd(int x, int y) { return y ? gcd(y, x % y) : x; }
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }

vvi board;
int h, w;

bool inside(int x, int y) {
	return 0 <= x && x < w && 0 <= y && y < h;
}

void change(int x, int y, vvi &vv) {
	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < 3; j++) {
			if (inside(x - 1 + j, y - 1 + i)) {
				vv[y - 1 + i][x - 1 + j] ^= 1;
			}
		}
	}
}

int chack(vvi board) {
	int res = 0;
	vvi chackBoard = board;
	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++) {
			if (chackBoard[i][j]) {
				if (!inside(j + 1, i + 1)) return INF;
				res++;
				change(j + 1, i + 1, chackBoard);
			}
		}
	}

	return res;
}


int dfs(int x, int y) {
	if (x == w) return dfs(0, 1);
	if (y == h) return chack(board);

	int res = INF;
	if (y == 0) {
		res = min(res, dfs(x + 1, y));
		change(x, 0, board);
		res = min(res, dfs(x + 1, y) + 1);
		change(x, 0, board);
	} else {
		res = min(res, dfs(x, y + 1));
		change(0, y, board);
		res = min(res, dfs(x, y + 1) + 1);
		change(0, y, board);
	}

	return res;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> h >> w;
	board.resize(h, vi(w));
	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++) {
			cin >> board[i][j];
		}
	}

	int res = dfs(0, 0);
	cout << (res >= INF / 2 ? "Impossible" : to_string(res)) << endl;
	return 0;
}