#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>

using namespace std;



long long bs(long long R, long long G, long long B){
	// [lb, ub)
	long long lb = 0;
	long long ub = max(R, max(G,B) ) + 1;
	while(ub-lb > 1){
		long long med = (ub+lb)/2;
		
		vector<long long> color(3);
		color[0] = R-med;
		color[1] = G-med;
		color[2] = B-med;

		for(int i=0; i<3; i++){
			for(int j=1; j<=2; j++){
				
				if(color[i] < 0){
					if(color[(i+j)%3] > 0){
						long long x = min( abs(color[i]), color[(i+j)%3]/2);
						color[i] += x;
						color[(i+j)%3] -= x*2;
					}
				}
				
			}
		}

		if(color[0] < 0 || color[1] < 0 || color[2] < 0){
			ub = med;
		}else{
			lb = med;
		}
	}
	return lb;
}

int main(){
	int R,G,B;
	cin >> R >> G >> B;
	cout << bs(R,G,B) << endl;

	
	return 0;
}