#include <bits/stdc++.h>
using namespace std;
long long a[5];
int main() {
  cin >> a[0] >> a[1] >> a[2];
  sort(a, a + 3);
  if (a[2] >= 2 * (a[0] + a[1]))
    cout << a[0] + a[1] << endl;
  else
    cout << (a[0] + a[1] + a[2]) / 3 << endl;
  return 0;
}
