row,col = input().split() row,col = int(row),int(col) a = [] for r in range(row): b = input().split() for i in range(len(b)): b[i] = int(b[i]) a.append(b) res = 0 for i in range(row): for in range(col): if i==0 or i==row-1 or j==0 or j==col-1: res = res + a[i][j] print(res)