class program {

void Girar(n) {
    iterate(n) turnleft();
}

void Explota(n) {
    if (!iszero(n) &&
        nextToABeeper) {
        pickbeeper();
        Explota(pred(n));
        putbeeper();
    } else if (iszero(n) &&
        notNextToABeeper) {
        turnleft();             
    }
}

void DarPasoAdelante() {
    if (frontIsBlocked) {
        if (facingEast) {
            turnleft();
            if (frontIsBlocked)
                turnoff();
            else move();
            turnleft();
        } else {
            Girar(3);
            if (frontIsBlocked)
                turnoff();
            else move();
            Girar(3);
        }
    } else move();
}

void RecorrerMundo(n) {
    if (nextToABeeper) {
        Explota(n);
        if (facingNorth ||
            facingSouth) {
            turnoff();
        }
        Explota(pred(n));
        if (facingNorth ||
            facingSouth) {
            turnleft();
            if (frontIsClear) {
                move();
                turnoff();
            }
            Girar(2);
        }
        Explota(succ(n));
        if (facingNorth ||
            facingSouth) {
            Girar(3);
            if (frontIsClear) {
                move();
                turnoff();
            }
        }
    }
    DarPasoAdelante();
    RecorrerMundo(succ(n));
}

program() {
    while (notFacingEast)
        turnleft();
    RecorrerMundo(0);
    turnoff();
}

}