import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

def Binary_Search(RGB, N):
	#初期化
	left = 0
	right = N
	ans = 0
	
	#二分探索
	while left <= right:
		mid = (left + right) // 2
		val = 0
		for i in range(3): 
			if RGB[i] - mid < 0:
				val += RGB[i] - mid
			else:
				val += int((RGB[i] - mid) // 2)

		if val >= 0:
			ans = max(ans, mid)
			left = mid + 1
		else:
			right = mid - 1

	return ans

#処理内容
def main():
	R, G, B = getlist()
	RGB = [R, G, B]
	N = 10 ** 7
	ans = Binary_Search(RGB, N)
	print(ans)


if __name__ == '__main__':
	main()