#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
#include <cmath>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

bool hantei(int r, int g, int b){
	int sum = r + g + b;
	int maxx = max(r, max(g, b));
	int minn = min(r, min(g, b));
	int midd = sum - (maxx + minn);
	if(maxx - minn >= 3) return true;
	return false;
}

int main(void){
	int r, g, b; cin >> r >> g >> b;
	int ma = max(r, max(g, b));
	int mi = min(r, min(g, b));
	while(ma - mi >= 3){
		ma -= 2;
		mi += 1;
		ma = max(r, max(g, b));
		mi = min(r, min(g, b));
	}
	printf("%d\n", mi);
}