#include <bits/stdc++.h>
#define p(s) cout<<(s)<<endl
typedef long long ll;
using namespace std;

ll R,G,B;
bool C(ll mid){
	ll num = 0;
	if(R > mid) num+=(R-mid)/2;
	if(G > mid) num+=(G-mid)/2;
	if(B > mid) num+=(B-mid)/2;
	if(mid-R > 0) num-=mid-R;
	if(mid-G > 0) num-=mid-G;
	if(mid-B > 0) num-=mid-B;
	return num>=0;
}


int main(){
	cin>>R>>G>>B;
	ll lb=0,ub=1e8;
	while(ub-lb>1){
		ll mid=(lb+ub)/2;
		if(C(mid)) lb=mid;
		else ub=mid;
	}
	p(lb);
	return 0;
}