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