/in/foo.cc: In function 'int main()':
/in/foo.cc:25:13: warning: unused variable 'l' [-Wunused-variable]
  for(ll i=1,l,r;i<=n;++i)
             ^
/in/foo.cc:25:15: warning: unused variable 'r' [-Wunused-variable]
  for(ll i=1,l,r;i<=n;++i)
               ^