def ishi(R, G, B):
    l = [R, G, B]
    l = sorted(l)
    while l[0] + 1 < l[2]:
        l[2] = l[2] - 2
        l[0] = l[0] + 1
        l = sorted(l)
    return l[0]

def main():
    R, G, B = map(int, input().split())
    print(ishi(R, G, B))

if __name__ == '__main__':
    main()