func_code_string: #include <bits/stdc++.h>   using namespace std;   void change(char &x) {     if (x ==  B )       x =  W ;     else       x =  B ;   }   int main() {     string s;     int n;     cin >> n;     cin >> s;     int w = 0, b = 0;     for (int i = 0; i < n; i++) {       if (s[i] ==  B )         b++;       else         w++;     }     if (b % 2 != 0 && w % 2 != 0) {       cout << -1;       return 0;     }     string c = s;     vector<int> vec1, vec2;     for (int i = 0; i < n - 1; i++) {       if (s[i] ==  B ) {         vec1.push_back(i + 1);         if (s[i] ==  B ) change(s[i]);         change(s[i + 1]);       }     }     if (s[n - 1] ==  W ) {       cout << vec1.size() << endl;       for (int i = 0; i < vec1.size(); i++) cout << vec1[i] <<    ;       return 0;     }     for (int i = 0; i < n - 1; i++) {       if (c[i] ==  W ) {         vec2.push_back(i + 1);         change(c[i]);         change(c[i + 1]);       }     }     if (s[n - 1] ==  B ) {       cout << vec2.size() << endl;       for (int i = 0; i < vec2.size(); i++) cout << vec2[i] <<    ;       return 0;     }     return 0;   }   