#include<bits/stdc++.h> using namespace std; int a[100][100]; int main(){ int n,m,sum=0; scanf("%d %d",&n,&m); //2wcin for(int i=1;i<=n;i++){//h for(int j=1;j<=m;j++){//l scanf("%d",&a[i][j]); if(i==1 ||i==n||j==1||j==m){ sum +=a[i][j]; } } } printf("%d\n",sum); }