/in/foo.cc: In function 'int Input(int&)':
/in/foo.cc:16:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int Output(int)':
/in/foo.cc:22:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^