a, b, c, bosuna = map(int, input().split())
#コンボ付きでのダメージ
combo = a + b + c + bosuna
waza = []
waza.append(a)
waza.append(b)
waza.append(c)
waza = sorted(waza)
saidai = waza[2]
saidai = saidai * 3
if combo > saidai:
  print(combo)
else:
  print(saidai)