var n = Int(readLine()!)!

var inputsX = [Int]()
var inputsY = [Int]()

for i in 1...n {
    var arr = readLine()!.characters.split(" ").map{Int(String($0))!}
    inputsX.append(arr[0])
    inputsY.append(arr[1])
}

func test(arrayToTest: [Int]) -> Bool{
    var current = -1
  
    for el in arrayToTest{
        if current == -1{
            current = el
        }
        if current != el{
            return false
        }
    }
    return true
}

let res = test(inputsX) || test(inputsY)

if res == true {
    print("YES")
}
else{
    print("NO")
}