func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, ans;   string str;   long long solve() {     long long k;     cin >> n >> k;     long long t = 3 * n;     while (t > k) {       t--;       ans++;     }     cout << ans;     return 0;   }   signed main() {     ios::sync_with_stdio(0);     long long t = 1;     while (t--) solve();     return 0;   }   