#include <bits/stdc++.h>   using namespace std;   static int LOCAL = 0;   const long long int mod = 1000000007ll;   const long long int MOD = 1000000009ll;   const long long int INF = LLONG_MAX / 10;   const int inf = INT_MAX / 10;   long long int powermod(long long int _a, long long int _b,                          long long int _m = mod) {     long long int _r = 1;     while (_b) {       if (_b % 2 == 1) _r = (_r * _a) % _m;       _b /= 2;       _a = (_a * _a) % _m;     }     return _r;   }   long long int power(long long int _a, long long int _b) {     long long int _r = 1;     while (_b) {       if (_b % 2 == 1) _r = (_r * _a);       _b /= 2;       _a = (_a * _a);     }     return _r;   }   long long int add(long long int a, long long int b, long long int m = mod) {     long long int x = a + b;     while (x >= m) x -= m;     return x;   }   long long int sub(long long int a, long long int b, long long int m = mod) {     long long int x = a - b;     while (x < 0) x += m;     return x;   }   long long int mul(long long int a, long long int b, long long int m = mod) {     return ((a % m) * (b % m)) % m;   }   long long int gcd(long long int a, long long int b) {     while (a && b) a > b ? a %= b : b %= a;     return a + b;   }   long long int lcm(long long int a, long long int b) {     return (max(a, b) / gcd(a, b)) * min(a, b);   }   struct pair_hash {     std::size_t operator()(const std::pair<int, int> &p) const {       auto h1 = std::hash<long long int>{}(p.first);       auto h2 = std::hash<long long int>{}(p.second);       return (int)add(h1, mul(h2, h1, MOD));     }   };   struct cmp {     bool operator()(pair<int, pair<long long int, long long int> > const &l,                     pair<int, pair<long long int, long long int> > const &r) {       return l.second.first < r.second.first;     }   } myobject;   multiset<int> second;   int main() {     int n, x;     cin >> n;     double sum = 0;     for (int i = 1; i <= n; i++) scanf( %d , &x), second.insert(x), sum += x;     double avg = sum / n;     int cnt = 0;     while (!(avg >= 4.50)) {       x = *second.begin();       second.erase(second.begin());       sum -= x;       sum += 5;       avg = sum / n;       cnt++;     }     cout << cnt;     return 0;   }   