#include <algorithm>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
#define rep(i,x) for(int i=0;i<(int)(x);++i)

int main(){
	int ans, min, a[3], *mn, *mx;
	rep(i,3) cin >> a[i];
	ans = *min_element(a, a+3);
	rep(i,3) a[i] -= ans;
	while (1) {
		mx = max_element(a, a+3);
		mn = min_element(a, a+3);
		++a[mn-a];
		a[mx-a] -= 2;
		mn = min_element(a, a+3);
		if (*mn < 1) break;
		++ans;
		rep(i,3) --a[i];
	}
	cout << ans << endl;
	return 0;
}