POJ 2864

 #include <iostream>
 #define MAXN 600
 using namespace std;

 int _m[MAXN][MAXN];

 int main()
 {
     //freopen("acm.acm","r",stdin);
     int c;
     int r;
     int i;
     int j;
     int sum;

     while(cin>>c>>r,c||r)
     {

     for(i = ; i < r; ++ i)
     {
         for(j = ; j < c; ++ j)
         {
             cin>>_m[i][j];
         }
     }

     for(j = ; j < c; ++ j)
     {
         sum = ;
         for(i = ; i < r; ++ i)
         {
             //sum += _m[i][j];
             if(_m[i][j] == )
             {
                 break;
             }
         }
         if(i == r)
         {
             cout<<"yes"<<endl;
             break;
         }
     }
     if(j == c)
     {
         cout<<"no"<<endl;
     }
     }

 }