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

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

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

def get_node(root, height, road, current_label):
    current = root
    for move in road:
        if move.lower() == 'l':
            if current.left is None:
                current.left = build_tree_lazy(height - 1, current_label)
            current = current.left
        elif move.lower() == 'r':
            if current.right is None:
                current.right = build_tree_lazy(height - 1, current_label)
            current = current.right
        height -= 1
    return current

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

    current_label = [root_label]
    root = build_tree_lazy(height, current_label)
    target_node = get_node(root, height, road, current_label)
    return target_node.label

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

    print(search_node(height, road))

main()