// 🐋💭
import Foundation

func readInts() -> [Int] {
    return readLine()!.split(separator: " ").map { Int($0)! }
}



func main() {
    let n = Int(readLine()!)!
    var aryA = readInts()
    //_________________________ここまで入力
    aryA.sort()
    for i in 0..<n-1 {
        if aryA[i] == aryA[i+1] {
            print("No")
            return
        }
    }
    print("Yes")
}

main()



