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