Main.cc: In function 'int main()':
Main.cc:8:5: error: 'unordered_map' was not declared in this scope
    8 |     unordered_map<char,int> M;
      |     ^~~~~~~~~~~~~
Main.cc:5:1: note: 'std::unordered_map' is defined in header '<unordered_map>'; did you forget to '#include <unordered_map>'?
    4 | #include<cmath>
  +++ |+#include <unordered_map>
    5 | using namespace std;
Main.cc:8:19: error: expected primary-expression before 'char'
    8 |     unordered_map<char,int> M;
      |                   ^~~~
Main.cc:11:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |     for(int i=0;i<s.size();i++){
      |                 ~^~~~~~~~~
Main.cc:12:31: error: 'M' was not declared in this scope
   12 |         if(i>0&&s[i]==s[i-1]) M[s[i]]++ ;
      |                               ^
Main.cc:14:10: error: 'M' was not declared in this scope
   14 |     sort(M.begin().second,M.end().second);
      |          ^
Main.cc:14:5: error: 'sort' was not declared in this scope; did you mean 'sqrt'?
   14 |     sort(M.begin().second,M.end().second);
      |     ^~~~
      |     sqrt