roes,cols=input().split() rows,cols=int(rows),int(cols) a=[] for x in range(rows): b=input().split() for x in range(len(b)) b[x]=int(b[x]) a.append(b) res=0 for x in range(rows): for y in range(cols): if x==0 or y==0 or x==rows-1 or y==cols-1 res+=a[x][y] print(res)