#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for(int i=x;i<y;i++)
#define range(a) (a).begin(),(a).end()
#define print(A,n) rep(i,0,n){cout<<(i ? " ":"")<<A[i];}cout<<endl;
#define pprint(A,m,n) rep(j,0,m){print(A[j],n);}
const long mod=1e9+7;
const int size=1e3;
const int inf=1e9;
int main(){
 int X,Y,Z;
 cin>>X>>Y>>Z;
 if(X>=Y+Z) cout<<Y+Z<<endl;
 else if(Y>=X+Z) cout<<X+Z<<endl;
 else cout<<(X+Y+Z)/2<<endl;
}