#!/usr/bin/env pypy3


def in_place_compute(stones):
    ans = 0
    stones.sort()
    ans += stones[0]
    stones[1] -= stones[0]
    stones[2] -= stones[0]
    stones[0] -= stones[0]
    while stones[2] >= 2:
        stones.sort()
        stones[2] -= 2
        stones[0] += 1
        if not (stones[1] and stones[2]):
            continue
        ans += stones[0]
        stones[1] -= stones[0]
        stones[2] -= stones[0]
        stones[0] -= stones[0]
        stones.sort()
    return ans


def main():
    stones = list(map(int, input().split()))
    print(in_place_compute(stones))


if __name__ == '__main__':
    main()