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