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