#define ____ this
#define _____ const
#define ______ return
#define ________ operator

struct _{_&__;_():__(*____){}_(_&___):__(___){}_&________=(_ _____&){______*____;}};

_ ________-(_&,_&_){______ _;}
_ ________-(_ _____&,_ _____&){_ _;______ _;}
_ ________-(_&_){______ _;}

int main()
{
    _ _;
    _=_.__-_.__;
    -_- _-_;
}