//简单的dp

 #include<cstdio>

 #define Max(a,b) ((a)>(b)?(a):(b))

 int d[];

 int main()

 {

     int i,j,n,m,x,t,te;

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

     for(i=; i<=n; ++i)

     {

         for(j=; j<=m; ++j)

         {

             scanf("%d",&x);

             d[j] = x + Max(d[j],d[j-]);

         }

     }

     printf("%d\n",d[m]);

     return ;

 }