---

requests = []

def add_request():
    print("\n--- Add Request ---")
    while True:
        num = input("Request number: ").strip()
        if any(r["num"] == num for r in requests):
            print("This number already exists, try another.")
        else:
            break
    name = input("Client name: ").strip()
    device = input("Device type: ").strip()
    problem = input("Problem description: ").strip()
    while True:
        try:
            cost = float(input("Repair cost: "))
            if cost < 0:
                print("Cost cannot be negative.")
            else:
                break
        except ValueError:
            print("Enter a number.")
    requests.append({"num": num, "name": name, "device": device,
                     "problem": problem, "status": "new", "cost": cost})
    print("Request added.")

def show_all():
    print("\n--- All Requests ---")
    if not requests:
        print("No requests.")
        return
    for r in requests:
        print(f"#{r['num']} | {r['name']} | {r['device']} | {r['status']} | {r['cost']} rub.")
        print(f"  Problem: {r['problem']}")

def find_request():
    num = input("Request number: ").strip()
    for r in requests:
        if r["num"] == num:
            print(f"#{r['num']} | {r['name']} | {r['status']} | {r['cost']} rub.")
            return
    print("Not found.")

def change_status():
    num = input("Request number: ").strip()
    for r in requests:
        if r["num"] == num:
            new = input("New status (new / in progress / done): ").strip()
            if new in ("new", "in progress", "done"):
                r["status"] = new
                print("Status updated.")
            else:
                print("Invalid status.")
            return
    print("Not found.")

def delete_request():
    num = input("Request number: ").strip()
    for r in requests:
        if r["num"] == num:
            requests.remove(r)
            print("Request deleted.")
            return
    print("Not found.")

def statistics():
    if not requests:
        print("No requests.")
        return
    count = {"new": 0, "in progress": 0, "done": 0}
    for r in requests:
        count[r["status"]] = count.get(r["status"], 0) + 1
    for status, n in count.items():
        print(f"  {status}: {n}")

while True:
    print("\n1. Add  2. Show all  3. Find  4. Change status  5. Delete  6. Stats  0. Exit")
    choice = input("Choice: ").strip()
    if choice == "1": add_request()
    elif choice == "2": show_all()
    elif choice == "3": find_request()
    elif choice == "4": change_status()
    elif choice == "5": delete_request()
    elif choice == "6": statistics()
    elif choice == "0":
        print("Goodbye!")
        break
    else:
        print("Invalid choice.")