// No.2778 Is there Same letter?
package main

import (
	"fmt"
	"strings"
)

func main() {
	var n int
	fmt.Scan(&n)

	var s string
	fmt.Scan(&s)

	ans := false
	for _, v := range s {
		if strings.Count(s, string(v)) > 1 {
			ans = true
			break
		}
	}
	if ans {
		fmt.Println("Yes")
	} else {
		fmt.Println("No")
	}
}