func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, rooms = 0;     char a, b;     scanf( %d n , &n);     int arr[30];     for (int i = 0; i < 26; i++) arr[i] = 0;     for (int i = 0; i < 2 * (n - 1); i += 2) {       scanf( %c%c , &a, &b);       arr[(int)(a -  a )]++;       if (arr[(int)(tolower(b) -  a )] > 0)         arr[(int)(tolower(b) -  a )]--;       else         rooms++;     }     cout << rooms << endl;     return 0;   }   