#include <stdio.h>
n,m,i,j;long long x,y,a,t;main(){for(scanf("%d%d",&n,&m);i<n;++i){for(a=j=0;j<m;++j)scanf("%lld",&t),a+=t;*((a-=y-x)<0?&x:&y)+=a;}printf("%lld\n",x>y?x:y);}