func_code_string: #include <bits/stdc++.h>   using namespace std;   int distance(int x1, int y1, int x2, int y2) {     return (int)ceil(sqrt(pow(x2 - x1, 2) + pow(y2 - y1, 2)));   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int n, m, x, q, cnt = 0;     string t;     char ch;     map<char, vector<pair<int, int>>> keys;     int freq[26] = {0};     cin >> n >> m >> x;     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         cin >> ch;         if (!freq[ch -  a ]) freq[ch -  a ]++;         keys[ch].push_back(make_pair(i, j));       }     }     if (keys.count( S )) {       vector<pair<int, int>> shiftCords = keys[ S ];       vector<pair<int, int>> chCords;       for (int i =  a ; i <=  z ; i++) {         if (keys.count(i)) {           chCords = keys[i];           bool validDistance = 0;           for (int j = 0; j < (int)chCords.size(); j++) {             for (int k = 0; k < (int)shiftCords.size(); k++) {               if (distance(chCords[j].first, chCords[j].second,                            shiftCords[k].first, shiftCords[k].second) <= x) {                 freq[i -  a ]++;                 validDistance = 1;                 break;               }             }             if (validDistance) break;           }         }       }     }     cin >> q;     cin >> t;     for (int i = 0; i < q; i++) {       char c = t[i];       if (islower(c)) {         if (!freq[c -  a ]) {           cout << -1 << endl;           return 0;         }       } else {         c = tolower(c);         if (!keys.count( S ) || !freq[c -  a ]) {           cout << -1 << endl;           return 0;         } else {           if (freq[c -  a ] == 1) cnt++;         }       }     }     cout << cnt << endl;     return 0;   }   