#include <bits/stdc++.h>
using namespace std;
long long a[4];
int main() {
  for (int i = 1; i <= 3; ++i) cin >> a[i];
  sort(a + 1, a + 4);
  if (a[3] > (a[1] + a[2]) * 2)
    cout << a[1] + a[2];
  else
    cout << (a[1] + a[2] + a[3]) / 3;
  return 0;
}
