class TreeNode:
    def __init__(self, label):
        self.label = label
        self.left = None
        self.right = None

def build_tree(height):
    total_nodes = (2 ** (height + 1)) - 1
    current_label = [total_nodes]
    return build_tree_recursively(height, current_label)

def build_tree_recursively(height, current_label):
    if height < 0:
        return None

    node = TreeNode(current_label[0])
    current_label[0] -= 1

    node.right = build_tree_recursively(height - 1, current_label)
    node.left = build_tree_recursively(height - 1, current_label)

    return node

def search_node(height, road=""):
    root = (2 ** (height + 1)) - 1
    if not road:
        return root

    label = root
    local = 0

    for move in road:
        if move.lower() == 'l':  
            local = 2 * local + 1
        elif move.lower() == 'r':
            local = 2 * local + 2

    label -= local
    return label

def main():
    line = input().strip()
    parts = line.split()
    height = int(parts[0])
    road = parts[1] if len(parts) > 1 else ""

    root = build_tree(height)
    print(search_node(height, road))

main()