/in/foo.cc: In function 'int main()':
/in/foo.cc:42:14: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
      a|=(1<<x-1);
             ~^~
/in/foo.cc:57:14: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
      a|=(1<<x-1);
             ~^~