#include<bits/stdc++.h>
using namespace std;

int main(){
    int r,g,b;
    cin>>r>>g>>b;
    vector<int> a={r,g,b};
    sort(a.begin(),a.end());
    int ans=0;
    while(a[0]>=ans){
        ans=max(ans,a[0]);
        a[0]++,a[2]-=2;
        sort(a.begin(),a.end());
    }
    cout<<ans<<endl;
}