#!/bin/python

#import math
#import os
#import random
#import re
#import sys



#
# Complete the 'donustur' function below.
#
# The function is expected to return a STRING.
# The function accepts STRING kelimeGrubu as parameter.
#

def donustur(kelimeGrubu):
    rakam = [0,1,2,3,4,5,6,7,8,9]
    sayac = 0
    for i in kelimeGrubu:
        if i in rakam:
            sayac+=1
        
    if sayac!=0:
        print(kelimeGrubu)
    
    else:
    
        if len(kelimeGrubu)<4:
            listKelime = list(kelimeGrubu)
            listKelime[0] = str(listKelime[0]).lower()
            listKelime[1] = str(listKelime[1]).upper()
            listKelime[2] = str(listKelime[2]).lower()
            kelimeGrubu = ''.join([str(ba) for ba in listKelime])
            print(kelimeGrubu)
            
            
        
        if len(kelimeGrubu)>3 and len(kelimeGrubu)<7:
            print(kelimeGrubu.lower)
            
        if len(kelimeGrubu)>= 7:
            print(kelimeGrubu.upper())
    
            

if __name__ == '__main__':
   # fptr = open(os.environ['OUTPUT_PATH'], 'w')

  #  kelimeGrubu = raw_input()
    kelimeGrubu = input()
    result = donustur(kelimeGrubu)

  #  fptr.write(result + '\n')

   # fptr.close()