def greedy_change(n, coins):
    result = []
    for value, count in sorted(coins, key=lambda x: -x[0]):
        while count > 0 and n >= value:
            n -= value
            count -= 1
            result.append(value)
    return result if n == 0 else None


if __name__ == "__main__":
    coins = [(10, 3), (5, 2), (2, 5), (1, 10)]
    N = 28
    print(greedy_change(N, coins))