# -*- coding: utf-8 -*-
"""
Created on Tue Jun 18 10:16:10 2019

@author: edoardottt
"""

#INCREASING SEQUENCES (FROM 1 TO 2N) PRINTER
S=[0,0];
def stseq(n,i):
    if(i==n):
        print(S)
    else:
        if(i==0 and n==1):
            for j in range(1,(2*n)+1):
                S[i]=j
                stseq(n,i+1)
        else:
            if(i==0):
                for j in range(1,(2*n)+1):
                    S[i]=j
                    stseq(n,i+1)
            else:
                for j in range(1,(2*n)+1):
                    if(S[i-1]<j):
                        S[i]=j
                        stseq(n,i+1)
stseq(2,0)