foo.cc: In function 'int main()':
foo.cc:28:33: error: expected primary-expression before '/' token
   28 |             while(!ans.empty()){/
      |                                 ^
foo.cc:29:17: error: expected primary-expression before 'int'
   29 |                 int x=ans.top();
      |                 ^~~
foo.cc:32:21: error: 'x' was not declared in this scope
   32 |                 fz+=x*fm;
      |                     ^

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