# -*- coding: utf-8 -*-
"""
No.91 赤、緑、青の石
https://yukicoder.me/problems/no/91

"""
import sys
from sys import stdin
input = stdin.readline


def main(args):
    ans = 0
    stones = [int(x) for x in input().split()]

    stones.sort(reverse=True)
    m = stones[2]
    stones[0] -= m
    stones[1] -= m
    stones[2] -= m
    ans += m

    for i in range(100):
        stones.sort(reverse=True)
        if stones[1] == 0 and stones[2] == 0:
            m = stones[0] * 2 // 5
            ans += m
            break
        elif stones[0] == stones[1]:
            stones[2] += stones[0] //3
            stones[2] += stones[1] //3
            m = min(stones)
            ans += m
            break
        gap12 = stones[1] - stones[2]
        gap01 = stones[0] - stones[1]
        if gap12 * 2 > gap01:
            stones[2] = gap01 // 2
            stones[0] -= stones[2] * 2
        else:
            stones[2] = gap12
            stones[0] -= stones[2] * 2
        m = stones[2]
        stones[0] -= m
        stones[1] -= m
        stones[2] -= m
        ans += m


    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])