#include <bits/stdc++.h>
using namespace std;
int main() {
  long long a, b, c, sum;
  cin >> a >> b >> c;
  sum = a + b + c;
  vector<long long> v(3);
  v[0] = a, v[1] = b, v[2] = c;
  sort(v.begin(), v.end());
  if (sum % 3 == 1) v[2]--;
  if (sum % 3 == 2) {
    if ((v[2] - v[1]) >= 2)
      v[2] = v[2] - 2;
    else
      v[2]--, v[1]--;
  }
  if ((2 * (v[0] + v[1])) >= v[2]) {
    cout << sum / 3;
    return (0);
  } else {
    cout << (v[0] + v[1]);
  }
}
