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package main

import "fmt"
import "slices"
import "strconv"

func main() {
	var Nstr string
   	fmt.Scan(&Nstr)
	N, _ := strconv.Atoi(Nstr)
	
	var S string
   	fmt.Scan(&S)
	chars := []rune(S)
	
	
	foundChars := make([]rune, 0, N)
	for _, char := range chars {
		if slices.Contains(foundChars, char) {
			fmt.Println("Yes")
			return;
		}
		foundChars = append(foundChars, char)
	}
	fmt.Println("No")
}