#include <bits/stdc++.h>
using namespace std;
int main() {
  int long long r, g, b;
  cin >> r >> g >> b;
  r = min(r, (g + b) * 2);
  g = min(g, (r + b) * 2);
  b = min(b, (r + g) * 2);
  cout << (r + g + b) / 3 << endl;
  return 0;
}
