// Enter your code here 
let t = Int(readLine()!)!
var match = true
var x = [Int]()
var y = [Int]()
for var i in 0..<t {
    let tempArr = readLine()!.characters.split(" ").map({Int(String($0))!})
    x.append(tempArr[0])
    y.append(tempArr[1])
}

let xv = x[0]
let yv = y[0]

for var i in 1..<t {
    if xv != x[i] {
        match = false
        break
    }
}

if match == true {
    print("YES")
}

else {
    match = true
    for var i in 1..<t {
    if yv != y[i] {
        match = false
        break
    }

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


}