#include <bits/stdc++.h>
using namespace std;

int main() {
    int h, w;
    cin >> h >> w;
    vector<int> a(h);
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            int t;
            cin >> t;
            a[i] |= t << j;
        }
    }
    
    vector<int> cost(1 << w, 1e6);
    for (int i = 0; i < 1 << w; i++) {
        int m = 0;
        int c = 0;
        for (int j = 0; j < w; j++) {
            if (i >> j & 1) {
                c++;
                if (j - 1 >= 0) {
                    m ^= 1 << (j - 1);
                }
                if (j + 1 < w) {
                    m ^= 1 << (j + 1);
                }
                m ^= 1 << j;
            }
        }
        cost[m] = min(cost[m], c);
    }

    int ans = 1e6;
    for (int ii = 0; ii < 1 << w; ii++) {
        int c = cost[ii];
        int prev = a[0] ^ ii;
        int next = ii;
        for (int i = 1; i < h; i++) {
            int curr = a[i] ^ next;
            next = prev;
            c += cost[next];
            prev = curr ^ next;
        }
        if (prev == 0) {
            ans = min(ans, c);
        }
    }
    if (ans >= 1e6) {
        puts("Impossible");
    } else {
        cout << ans << endl;
    }
}