text: #include <bits/stdc++.h>
  using namespace std;
  
  int main() {
      int n = 12; 
      double balance, total {0};
  
      while(n--) {
          cin >> balance;
          total += balance;
      }
  
      cout << "$" << static_cast<double>(total / 12) << endl;
      return 0;
  }
  