#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int a[3];
  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;
}
