import sys
input = sys.stdin.readline


def main():
    def isOK(m):
        r = R - m
        g = G - m
        b = B - m
        cnt = 0
        for s in [r, g, b]:
            if s>=0:
                cnt += s//2
        for s in [r, g, b]:
            if s<0:
                cnt += s
        return cnt >= 0


    def binary_search(ok, ng):
        while abs(ok - ng) > 1:
            mid = (ok + ng) // 2
            if isOK(mid):
                ok = mid
            else:
                ng = mid
        return ok
    

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

    ok = -1
    ng = 10000010
    print(binary_search(ok, ng))


if __name__ == '__main__':
    main()