#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"
#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout<<(p)<<endl;
#define pi 3.1415926535
using namespace std;
typedef long long ll;
int dx[] = { 0, 1, 0, -1 };
int dy[] = { -1, 0, 1, 0 };

unsigned long long sttoi(std::string str) {
	unsigned long long ret;
	std::stringstream ss; ss << str;
	ss >> ret;
	return ret;
}

bool isPrime(ll n){
	if (n % 2 == 0)return false;
	for (ll i = 3; i*i <= n; i += 2){
		if (n%i == 0)return false;
	}
	return true;
}

void solve() {
	int s[3];
	cin >> s[0] >> s[1] >> s[2];
	int left = 0, right = 100000000;
	while (right-left > 1){
		int mid = (left + right) / 2;
		int x = 0;
		rep(i, 3)x += s[i] > mid ? (s[i] - mid)/2 : 0;
		rep(i, 3)x -= s[i] < mid ? mid - s[i] : 0;
		if (x >= 0)
			left = mid;
		else 
			right = mid;
	}
	P(left);
}

int main() {
	solve();
	return 0;
}