#include <bits/stdc++.h>   using namespace std;   int main() {     string s;     int n;     cin >> n >> s;     vector<int> vec;     for (int i = 0; i < s.length(); ++i) {       if (s[i] ==  B ) {         int res = 0;         while (i < s.length() && s[i] ==  B ) {           ++res;           ++i;         }         vec.push_back(res);         continue;       }     }     cout << vec.size() <<   n ;     for (int i = 0; i < (int)vec.size(); ++i) {       cout << vec[i] <<    ;     }     cout <<   n ;   }   