def main():
    S = input()

    i = len(S)
    road = [j for j in range(2 ** i, (2 ** i) * 2)]
    for s in S:
        i = len(road) // 2
        if s == 'L':
            road = road[0:i]
        else:
            road = road[i:]

    print(road[0])

main()