S = input()
A = [i for i in range(2**len(S), 2**len(S)*2)]
start = 0
end = len(A)-1
for c in S:
	if c == 'L':
		end = (end - start)//2 + start
	else:
		start = (end - start)//2 + start + 1
print(A[start])