<?php
function traverse($S, $idx) {
return;
}
traverse($S, $idx + 1);
return;
}
traverse("abc", 0);
PD9waHAKCmZ1bmN0aW9uIHRyYXZlcnNlKCRTLCAkaWR4KSB7CiAgaWYgKCRpZHggPT0gIHN0cmxlbigkUykpIHsKICAgICAgICBwcmludF9yKCRTKTsKICAgICAgICByZXR1cm47CiAgfQogIHRyYXZlcnNlKCRTLCAkaWR4ICsgMSk7CiAgdHJhdmVyc2Uoc3Vic3RyX3JlcGxhY2UoJFMsIHN0cnRvdXBwZXIoJFNbJGlkeF0pLCAkaWR4LCAxKSwgJGlkeCArIDEpOwogIHJldHVybjsKfQoKdHJhdmVyc2UoImFiYyIsIDApOw==