#include <iostream>
#include <fstream>
using namespace std;
ifstream f("flip.in") ;
ofstream g("flip.out") ;
int main()
{
    int n , m  , i , j , s = 0 , o[17][17] ;
     f >> n >> m ;
    for ( i = 1 ; i<=n ; i ++ )
        for ( j = 1 ; j <= m ; j ++ )
          {
            f >> o[i][j] ;
            if ( o[i][j] > 0 )
                s = s + o[i][j] ; }
            g << s ;

    return 0;
}