#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000



int main(){
	
	int r,g,b;
	cin>>r>>g>>b;
	
	int ok = -1,ng = 1000000000;
	while(ng-ok>1){
		int mid = (ok+ng)/2;
		int rr = r,gg = g,bb = b;
		
		rr -= mid;
		gg -= mid;
		bb -= mid;
		int A = 0,B = 0;
		if(rr<0){
			B-=rr;
		}
		else{
			A += rr/2;
		}
		if(gg<0){
			B-=gg;
		}
		else{
			A += gg/2;
		}
		if(bb<0){
			B-=bb;
		}
		else{
			A += bb/2;
		}
		if(A>=B)ok = mid;
		else ng = mid;
	}
	
	cout<<ok<<endl;

	
	return 0;
}