while True:
    num_def, num_atc = [int(x) for x in input().split()]
    if num_def == num_atc == 0:
        break
    
    dist_atc = [int(x) for x in input().split()]
    dist_def = [int(x) for x in input().split()]

    min_dist_atc = min(dist_atc)
    dist_def.sort()
    seg_dist_def = dist_def[1]

    impedido = 'Y' if min_dist_atc < seg_dist_def else 'N'
    print(impedido)