def c(x):
    # x個作ることが可能か
    global R, G, B
    ret = 0
    for a in (R, G, B):
        if a>=x:
            ret += (a-x)//2
        else:
            ret += a-x
    return ret>=0

R, G, B = map(int, input().split())
inf = 0
sup = 10**9
while sup-inf>1:
    mid = (inf+sup)//2
    if c(mid):
        inf = mid
    else:
        sup = mid
print(inf)