#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c;
  cin >> a >> b >> c;
  long long int ans = a / 3 + b / 3 + c / 3 + min(a % 3, min(b % 3, c % 3));
  if ((a % 3 == 2 && b % 3 == 2 && c % 3 != 2 && c != 0) ||
      (a % 3 == 2 && c % 3 == 2 && b % 3 != 2 && b != 0) ||
      (c % 3 == 2 && b % 3 == 2 && a % 3 != 2 && a != 0))
    ans++;
  cout << ans << endl;
  return 0;
}
