n,m = map(int,input().split()) lst = [] for i in range(n): lst.append(list(map(int,input().split()))) if n == 1: print(1) else: s = 0 s = s+sum(lst[0]) s = s+sum(lst[-1]) for i in range(1,n-1): s = s+lst[i][0] + lst[i][-1] print(s)