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

int main() {
    int r,g,b;
    cin>>r>>g>>b;
    if (r>g)swap(r,g);
    if (r>b)swap(r,b);
    if (g>b)swap(g,b);
    while (r+1<=b-2) {
        b-=2;
        r++;
        if (r>g)swap(r,g);
        if (r>b)swap(r,b);
        if (g>b)swap(g,b);
    }
    cout<<r<<endl;
    return 0;
}