#include <iostream> #include <sstream> #include <iomanip> #include <cstdio> #include <cassert> #include <algorithm> #include <iterator> #include <string> #include <vector> #include <list> #include <deque> #include <set> #include <unordered_set> #include <map> #include <unordered_map> #include <tuple> #include <queue> #include <stack> #include <functional> #include <utility> #include <complex> #include <bitset> #include <numeric> #include <random> using namespace std; #define REP(i,n) for(int (i)=0; (i)<(n) ;++(i)) #define REPN(i,a,n) FOR((i),(a),(a)+(n)) #define FOR(i,a,b) for(int (i)=(a); (i)<(b) ;++(i)) #define PB push_back #define MP make_pair #define SE second #define FI first #define DBG(a) cerr<<(a)<<endl; #define dump(a) cerr<<#a <<' '<< a <<endl; #define ALL(v) (v).begin(),(v).end() typedef long long LL; typedef pair<LL, LL> PLL; typedef vector<LL> VLL; typedef pair<int,int>PI; typedef vector<int> VI; const LL LINF=334ll<<53; const int INF=15<<26; const LL MOD=1E9+7; int main(){ cin.tie(0); ios::sync_with_stdio(false); int n,m; cin >> m >> n; vector<VI> res(m+2,VI(n+2)); REP(i,m){ REP(j,n){ cin >> res[i+1][j+1]; } } int ans=INF; REP(i,(1<<(m+n-1))){ vector<VI>flip(m+2,VI(n+2)); int cnt=0; REP(j,n) flip[1][j+1]=((i>>j)&1); FOR(j,1,m) flip[j+1][1]=((i>>(n+j-1))&1); FOR(j,1,m+1){ FOR(k,1,n+1){ flip[j+1][k+1]=res[j][k]; REP(h,3){ REP(g,(h==2?2:3)){ flip[j+1][k+1]^=flip[j-1+h][k-1+g]; } } cnt+=flip[j+1][k+1]; if((j==m or k==n)and flip[j+1][k+1]==1) cnt=INF; } } cnt+=__builtin_popcount(i); ans=min(ans,cnt); } if(ans==INF)cout << "Impossible"<<endl; else cout << ans <<endl; return 0; }