import sys
sys.setrecursionlimit(500000)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
from collections import defaultdict,deque
import bisect
import itertools
dic = defaultdict(int)
d = deque()
a,b,c,d = MI()
print(max(a+b+c+d,max(a,b,c)*3))