m,n = input().split() m = int(m) n = int(n) a = [] for i in range(m): tmp = input().split() a.append(tmp) s=0 for i in range(m): for j in range(n): if i==0 or i==m-1 or j==0 or j == n-1: s=s+int(a[i][j]) print(s)