/* -*- coding: utf-8 -*-
 *
 * 460.cc: No.460 裏表ちわーわ - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_H = 8;
const int MAX_W = 8;
const int WBITS = 1 << MAX_W;
const int INF = 1 << 30;

/* typedef */

/* global variables */

int h, w, wbits;
int bds[MAX_H];
int msks[MAX_W], mbits[WBITS], bnums[WBITS];
int minc;

/* subroutines */

inline int xy2p(int x, int y) { return y * w + x; }

void rec(int y, int c) {
  if (y >= h) {
    if (bds[h - 1] == 0 && minc > c) minc = c;
    return;
  }

  for (int bits = 0; bits < wbits; bits++)
    if (bds[y - 1] == mbits[bits]) {
      bds[y] ^= mbits[bits];
      if (y < h - 1) bds[y + 1] ^= mbits[bits];
      rec(y + 1, c + bnums[bits]);
      if (y < h - 1) bds[y + 1] ^= mbits[bits];
      bds[y] ^= mbits[bits];
    }
}

/* main */

int main() {
  cin >> h >> w;
  wbits = 1 << w;
  
  for (int y = 0; y < h; y++)
    for (int x = 0, bi = 1; x < w; x++, bi <<= 1) {
      int a;
      cin >> a;
      if (a) bds[y] |= bi;
    }

  for (int x = 0, bi = 1; x < w; x++, bi <<= 1) {
    msks[x] = bi;
    if (x > 0) msks[x] |= (bi >> 1);
    if (x < w - 1) msks[x] |= (bi << 1);
  }

  for (int bits = 0; bits < wbits; bits++) {
    mbits[bits] = bnums[bits] = 0;
    for (int x = 0, bi = 1; x < w; x++, bi <<= 1)
      if (bits & bi) mbits[bits] ^= msks[x], bnums[bits]++;
  }

  minc = INF;

  for (int bits = 0; bits < wbits; bits++) {
    bds[0] ^= mbits[bits]; bds[1] ^= mbits[bits];
    rec(1, bnums[bits]);
    bds[0] ^= mbits[bits]; bds[1] ^= mbits[bits];
  }

  if (minc >= INF) puts("Impossible");
  else printf("%d\n", minc);
  return 0;
}