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