import itertools

receipt_totals = [
    7.73,
    56.85,
    7.73,
    30.80,
    6.60,
    16.87,
    23.50,
    4.77,
    2.78,
    19.81,
    40.89,
    2.90,
    5.76,
    18.58,
    4.66,
    2.99,
    1.99,
    7.47,
    13.00,
]
for r in range(1, len(receipt_totals)):
    r_combos = [
        x for x in itertools.combinations(receipt_totals, r) if sum(x) == 171.76
    ]
    if r_combos:
        print("combos with " + str(r) + " receipts equaling $171.76: ")
        for combo in r_combos:
            print(combo)