a1, a2, a3, b = map(int, input().split())
aList = [a1,a2,a3]

dmc = a1 + a2 + a3 + b
aList = sorted(aList)
dmnc = aList[2] * 3

dmax = 0
if dmc > dmnc:
    dmax = dmc
else:
    dmax = dmnc

print(dmax)