import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt();
        String temp=in.next();
        char x=temp.charAt(0);
        int ans=0;
        StringBuffer a=new StringBuffer();
        for (int i=1;i<=n;i++){
            a.append(i);
        }
        for (int i=0;i<a.length();i++){
            if (a.charAt(i)==x){
                ans++;
            }
        }
        System.out.println(ans);
    }

}