from array import array
import csv
a = array('i')
b = array('i')
for anum, bnum in csv.reader(open('input.csv', 'rb')):
    a.append(int(anum))
    b.append(int(bnum))
wtr = csv.writer(open('output.csv', 'wb'))
for i in sorted(xrange(len(a)), key=lambda x: b[x]):
    wtr.writerow([a[i], b[i]])