# Copyright David Abrahams 2006. Distributed under the Boost
# Software License, Version 1.0. (See accompanying
# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

class frame:
    def __init__(self, level):
        self.level = (level + 3)/4
        self.children = 0
        
def tree4(n):
    stack = [frame(n)]
    i = 0
    
    while stack:
        
        top = stack[-1]
        if top.children == 4 or i == n:
            print '>',
            stack.pop()
        else:
            if top.children == 0:
                print 'mpl::and<',
            else:
                print ',',
                
            top.children += 1
            
            if top.level == 1 or i == n - 1:
                print 'p%s'%i,
                i += 1
            else:
                stack.append(frame(top.level))

    print
            
for x in range(1,30):
    print '%s:\t'%x,
    tree4(x)