/in/foo.cc: In function 'int main()':
/in/foo.cc:49:11: warning: unused variable 'tf' [-Wunused-variable]
  ll ans=0,tf=0,tb=0,lastx=0;
           ^~
/in/foo.cc:49:16: warning: unused variable 'tb' [-Wunused-variable]
  ll ans=0,tf=0,tb=0,lastx=0;
                ^~