#!/usr/bin/python
import sys

inf = sys.argv[1]
inf = open(inf)
input = inf.read()
inf.close()

output = '';

for i in range(0,len(input)/2):
	output = output + input[i*2+1] + input[i*2]

outf = sys.argv[2]
outf = open(outf,'wb')
outf.write(output)
outf.close()