# https://yukicoder.me/problems/no/1163

MAX_INT = 10 ** 18

def main():
    N, X = map(int, input().split())
    A = list(map(int, input().split()))
    B = list(map(int, input().split()))

    C = [(A[i] - X, B[i]) for i in range(N)]

    value_map = {}
    answer = -1
    for a, b in C:
        new_value_map = value_map.copy()
        for key, value in value_map.items():
            if (key + a) not in new_value_map:
                new_value_map[key + a] = -1
            new_value_map[key + a] = max(new_value_map[key + a], value + b)
        if a not in new_value_map:
            new_value_map[a] = -1
        new_value_map[a] = max(new_value_map[a], b)

        value_map = new_value_map

    answer = MAX_INT
    sum_b = sum(B)
    for key, value in value_map.items():
        if key >= 0:
            answer = min(answer, sum_b - value)
    
    if answer == MAX_INT:
        print(-1)
    else:
        print(answer)


if __name__ == "__main__":
    main()