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

int main(void){
	int r, g, b; cin >> r >> g >> b;
	int sum = 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;
		sum--;
		ma = max(ma, max(mi, sum - ma - mi));
		mi = min(ma, min(mi, sum - ma - mi));
		// printf("%d %d\n", ma, mi);
	}
	printf("%d\n", mi);
}