Python :

 
zbs = []
class Zb:
    def __init__(self,x,y):
        self.x = x
        self.y= y

n=int(input())
for i in range(n):
  x,y=list(map(int,input().split()))
  zbs.append(Zb(x,y))

 

zbslist = sorted(zbs, key=lambda zz:(zz.x, zz.y))

 

for t in zbslist:
    print(t.x,t.y)