#include <bits/stdc++.h>
using namespace std;
int main() {
  long long a, b, c, A, B, C;
  long long arr[3];
  cin >> a >> b >> c;
  arr[0] = a;
  arr[1] = b;
  arr[2] = c;
  sort(arr, arr + 3);
  A = arr[0];
  B = arr[1];
  C = arr[2];
  if (C >= (2 * A + 2 * B)) {
    C = (2 * A + 2 * B);
  }
  long long ans = (A + B + C) / 3ll;
  cout << ans << endl;
}
