func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long int N = 100005;   void solve() {     long long int m, n;     cin >> n >> m;     long long int count = 0;     for (long long int i = 1; i <= n; i++) {       count += (m + i % 5) / 5;     }     cout << count << endl;     return;   }   int32_t main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     solve();     return 0;   }   