class program {

define half-turn() {
    turnleft();
    turnleft();
}

define go-back() {
    half-turn();
    while (frontIsClear) {
        move();
    }
    half-turn();
}

define tin-marin() {
    if (nextToABeeper) {
        pickbeeper();
        tin-marin();
        if (frontIsClear) {
            move();
        } else {
            go-back();
        }
    }
}

program() {
    pickbeeper();
    tin-marin();
    turnoff();
}

}