R, G, B = map(int, input().split())

ans = min(R, G, B)

R -= ans
G -= ans
B -= ans

l, r = 0, max(R, G, B) + 1

while r - l > 1:
    c = (l + r) // 2
    rest = 0
    for x in (R, G, B):
        if x > c:
            rest += (x - c) // 2
        elif x < c:
            rest -= c - x
    if rest >= 0:
        l = c
    else:
        r = c

ans += l
print(ans)