/in/foo.cc: In function 'int main()':
/in/foo.cc:20:13: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
     while(l1<=r1 & l2 <=r2){
           ~~^~~~
/in/foo.cc:37:13: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
     while(l1<=r1 & l2 <=r2){
           ~~^~~~