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