def check(x):
    global R, G, B
    ret = 0
    for a in (R, G, B):
        if a >= x:
            ret += (a - x) // 2 # 新たな石の生成数
        else:
            ret += a - x # 要求する石の数
    return ret >= 0 # 0は許容

R, G, B = map(int, input().split())
low, high = 0, int(1e9)
while abs(high - low) > 1:
    mid = (low + high) // 2
    if check(mid):
        low = mid
    else:
        high = mid
print(low)