Codeforces 358E

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <queue>
#include <cmath>
#include <stack>
#include <map>

#pragma comment(linker, "/STACK:1024000000");
#define EPS (1e-8)
#define LL long long
#define ULL unsigned __int64
#define _LL __int64
#define INF 0x3f3f3f3f
#define Mod 20090717

using namespace std;

bool vis[1002][1002][4];

int num[1010][1010];

int dir[2][4] = {{-1,0,1,0},{0,-1,0,1}};

int total;

int ans;

void dfs(int x,int y,int d,int len)
{
bool mark = false;
for(int i = 0;i < 4; ++i)
{
if(0 == num[x+dir[0][i]][y+dir[1][i]] || vis[x][y][i] == true)
continue;
vis[x][y][i] = true,vis[x+dir[0][i]][y+dir[1][i]][(i+2)%4] = true;

total -= 2;

if(d != -1 && i != d)
ans = __gcd(ans,len),dfs(x+dir[0][i],y+dir[1][i],i,1);
else
dfs(x+dir[0][i],y+dir[1][i],i,len+1);
mark = true;
}

if(mark == false)
ans = __gcd(ans,len);
}

int main()
{
#ifdef DouBi
freopen("in.cpp","r",stdin);
#endif // DouBi
int n,m,i,j,k;

scanf("%d %d",&n,&m);

memset(num,0,sizeof(num));

for(i = 1;i <= n; ++i)
for(j = 1;j <= m; ++j)
scanf("%d",&num[i][j]);

int odd = 0;

ans = 0;
total = 0;

for(i = 1;i <= n; ++i)
for(j = 1;j <= m; ++j)
{
if(num[i][j] == 0)
continue;
for(ans = 0,k = 0;k < 4; ++k)
ans += num[i+dir[0][k]][j+dir[1][k]];
total += ans;
if(ans == 0)
return puts("-1"),0;
if(ans&1)
odd++;
}

if(odd != 0 && odd != 2)
return puts("-1"),0;

memset(vis,false,sizeof(vis));

ans = 0;

for(i = 1;i <= n; ++i)
for(j = 1;j <= m; ++j)
if(num[i][j])
{
dfs(i,j,-1,0);
goto V;
}
V:;

if(total || ans <= 1)
return puts("-1"),0;

for(i = 2;i < ans; ++i)
if(ans%i == 0)
printf("%d ",i);
printf("%d\n",ans);
return 0;
}