/in/foo.cc: In function 'int main()':
/in/foo.cc:22:16: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'std::__cxx11::string* {aka std::__cxx11::basic_string<char>*}' [-Wformat=]
  scanf("%s",&ms);
                ^
/in/foo.cc:24:22: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[2]' [-Wformat=]
  while(scanf("%s",&ch)) {
                      ^
/in/foo.cc:26:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(st.size()>=len&&take(1)) {
      ~~~~~~~~~^~~~~