func_code_string: #include <bits/stdc++.h>   using namespace std;   signed main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long n, k;     cin >> n >> k;     map<char, long long> mp;     for (long long i = 0; i < n; i++) {       char x;       cin >> x;       mp[x]++;     }     vector<pair<long long, char>> v;     for (auto it : mp) {       pair<long long, char> p;       p.first = it.second;       p.second = it.first;       v.push_back(p);     }     sort(v.begin(), v.end(), greater<pair<long long, char>>());     long long ans = 0;     for (long long i = 0; i < v.size() && k > 0; i++) {       long long x = min(k, v[i].first);       ans += (x * x);       k -= x;     }     cout << ans << endl;     return 0;   }   