class TreeNode:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None
        self.height = 1

class AVLTree:
    def __init__(self):
        self.root = None

    def construct_avl(self, height):
        # Cria uma \xe1rvore AVL completa com base na altura
        total_nodes = (1 << (height + 1)) - 1
        self.root = self._build_tree(1, total_nodes)

    def _build_tree(self, start, end):
        if start > end:
            return None
        mid = (start + end) // 2
        node = TreeNode(mid)
        node.left = self._build_tree(start, mid - 1)
        node.right = self._build_tree(mid + 1, end)
        return node

    def find_node_label(self, height, path):
        cur = 1
        for c in path:
            cur = cur * 2 + (c == 'R')
        total_nodes = (1 << (height + 1)) - 1
        return total_nodes - cur + 1

if __name__ == "__main__":
    import sys
    input = sys.stdin.read
    data = input().strip().split()

    height = int(data[0])  # Altura
    path = data[1] if len(data) > 1 else "" 

    avl_tree = AVLTree()
    avl_tree.construct_avl(height)
    result = avl_tree.find_node_label(height, path)
    print(result)