#include <bits/stdc++.h>
using namespace std;
int main() {
  long long a[3];
  for (int i = 0; i < 3; i++) cin >> a[i];
  sort(a, a + 3);
  reverse(a, a + 3);
  if (a[0] >= 2 * (a[1] + a[2]))
    cout << a[1] + a[2] << "\n";
  else
    cout << (a[0] + a[1] + a[2]) / 3 << "\n";
  return 0;
}
