#include <bits/stdc++.h>
int main()
{
    long long n,m;
    long long tmp,s=0;
    scanf("%lld %lld",&n,&m);
    for (long long i=1;i<=n;i++)
    {
        for (long long j=1;j<=m;i++)
        {
            scanf("%lld",&tmp);
            if (i==1||j==1||i==n||j==m)
            {
                s+=tmp;
            }
        }
    }
    printf("%lld",s);
    return 0;  
}