N = input()
l = list(N)
length = len(N)
already_use = 0

for i in range(length):
    already_use += 2**i

new_load = 2 ** (length)
l_new_load = [i for i in range(1, new_load + 1)]
#print(l_new_load)

for i in range(length):
    if l[i] == "L":
        del l_new_load[len(l_new_load) // 2:]
        #print(l_new_load)
    else:
        del l_new_load[:len(l_new_load) // 2 ]
        #print(l_new_load)

print(already_use + l_new_load[0])