Codeforces New Year Transportation

题目链接：http://codeforces.com/problemset/problem/500/A

import java.util.Scanner;

public class NewYearTransportation {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
int t = scanner.nextInt();
int[] a = new int
;
for(int i = 1; i < n; i++) {
a[i] = i + scanner.nextInt();
}
int j = 1;
while(j < n) {
if(a[j] == t) {
System.out.println("YES");
return ;
}
j = a[j];
}
System.out.println("NO");
}
}