#include<bits/stdc++.h>
using namespace std;
int n,m,k;
int main(){
    cin>>n>>m>>k;
    int ans=0;
    for(int i=1;i<=max(n,m);i++){
        if(n<=1||m<1)break;
        n-=2;
        m-=1;
        ans++;
    }
    if(n>=k||m>=k){cout<<ans<<endl;return 0;}
    if(k%3!=0)ans-=k/3+1;
    else ans-=k/3;
    cout<<ans<<endl;
    return 0;
}