package main

import "fmt"

func main() {
	var (
		n int
		s string
		m map[rune]bool
	)
	fmt.Scan(&n,&s)
	for _,c := range s {
		if _,ok := m[c]; ok {
			fmt.Println("Yes")
			return
		}
		m[c]=true
	}
	fmt.Println("No")
}