#include <bits/stdc++.h>
using namespace std;
const int n = 3;
long long r, g, b;
void reset() {
  if (r >= g) swap(r, g);
  if (r >= b) swap(r, b);
  if (g >= b) swap(g, b);
}
int main() {
  while (cin >> r >> g >> b) {
    reset();
    if ((r + g) * 2 <= b)
      cout << r + g << endl;
    else
      cout << (r + g + b) / 3 << endl;
  }
  return 0;
}
