def solve():
    RGB = list(map(int, input().split()))
    RGB.sort()
    a, b, c = RGB

    def check(x):
        if b >= x:
            d = a + (b - x) // 2
            rest = c - (x - d) * 2
        else:
            rest = c - (x - a) * 2 - (x - b) * 2
        return rest >= x

    l = 0
    r = c + 1

    while r - l > 1:
        m = (r + l) // 2
        if check(m):
            l = m
        else:
            r = m

    print(l)


if __name__ == '__main__':
    solve()