import Foundation

let N = Int(readLine()!)!

var tuples = [(x: Int, y: Int)]()

for _ in 1...N {
    let xy = readLine()!.components(separatedBy: " ").map { Int($0)! }
    let x = xy[0]
    let y = xy[1]
    tuples.append((x, y))
}

tuples = tuples.sorted(by: { $0.y < $1.y }).sorted(by: { $0.x < $1.x })

for tuple in tuples {
    print(tuple.x, tuple.y)
}

ํŠœํ”Œ๋กœ ํ’€์—ˆ๋‹ค. ์ •๋ ฌํ• ๋•Œ๋Š” ์ •๋ ฌํ•˜๋Š” ์ˆœ์„œ๋ฅผ ์œ ์˜ํ•˜๋Š”๊ฒŒ ์ข‹์„ ๊ฒƒ ๊ฐ™๋‹ค.

๋ฐ˜์‘ํ˜•
JerryiOS