class program {

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

define turnright() {
    iterate(3) {
        turnleft();
    }
}

define putbeepers(n) {
    iterate (n) {
        putbeeper();
    }
}

define go-back() {
    if (nextToABeeper) {
        pickbeeper();
        go-back();
        putbeeper();
    } else {
        turnright();
        iterate (3) {
            if (notNextToABeeper && frontIsClear) {
                move();
                if (notNextToABeeper) {
                    half-turn();
                    move();
                    half-turn();
                }
            }
            if (notNextToABeeper) {
                turnleft();
            }
        }
        if (nextToABeeper) {
           go-back();
           move();
        } else {
            while (notFacingSouth) {
                turnleft();
            }
            move();
            turnleft();
        }
    }
}

define search() {
    if (nextToABeeper) {
        half-turn();
        move();
        go-back();
        turnoff();
    }
    turnright();
    iterate (3) {
        if (frontIsClear) {
            if (facingNorth) {
                putbeepers(2);
            } else if (facingEast) {
                putbeepers(3);
            } else if (facingSouth) {
                putbeepers(4);
            } else if (facingWest) {
                putbeepers(5);
            }
            move();
            search();
            move();
            half-turn();
            while (nextToABeeper) {
                pickbeeper();
            }
        }
        turnleft();
    }
}

program() {
    search();
    turnoff();
}

}