#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<long long> vec(3);
  cin >> vec[0] >> vec[1] >> vec[2];
  sort(vec.begin(), vec.end());
  if ((vec[0] + vec[1]) <= vec[2] / 2)
    cout << vec[0] + vec[1] << endl;
  else
    cout << (vec[0] + vec[1] + vec[2]) / 3 << endl;
  return 0;
}
