#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long a[3];
  cin >> a[0] >> a[1] >> a[2];
  sort(a, a + 3);
  if (a[2] > 2 * (a[0] + a[1])) a[2] = 2 * (a[0] + a[1]);
  cout << (a[0] + a[1] + a[2]) / 3;
}
