#include <bits/stdc++.h>
using namespace std;
int stones[3];
bool can(int x)
{
	int rem = 0, need = 0;
	for(int i = 0; i < 3; i++) {
		if(stones[i] > x) {
			rem += (stones[i] - x) / 2;
		}
		else {
			need += x - stones[i];
		}
	}
	if(rem >= need) return true;
	else return false;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	cin >> stones[0] >> stones[1] >> stones[2];
	int left = 0, right = 10000000;
	while(right - left > 1) {
		int mid = left + (right - left) / 2;
		if(can(mid)) left = mid;
		else right = mid;
	}
	cout << (can(right) ? right : left) << endl;
	return 0;
}