/in/foo.cc: In function 'long long int insert(long long int)':
/in/foo.cc:142:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'long long int del(long long int)':
/in/foo.cc:155:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^