m,n = input().split() m,n = int(m),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)