func_code_string: #include <bits/stdc++.h>   using namespace std;   long long pow1(long long a, long long b) {     if (b == 0) return 1;     if (b == 1) return a;     long long ab = pow1(a, b / 2) % 1000000007;     if (b % 2 == 0)       return (ab * ab) % 1000000007;     else       return ((ab * ab) % 1000000007 * a) % 1000000007;   }   int main() {     string s;     long long k;     cin >> s >> k;     long long ans = 0;     for (int i = (int)(s.size()) - 1; i >= 0; i--) {       if (s[i] ==  0  || s[i] ==  5 ) {         ans = (ans + pow1(2, i)) % 1000000007;       }     }     long long ha = pow1(2, (int)(s.size()) * k) - 1;     ha = (ha * pow1(pow1(2, (int)(s.size())) - 1, 1000000007 - 2)) % 1000000007;     ans = (ans * ha) % 1000000007;     cout << ans << endl;     return 0;   }   