import java.io.BufferedReader;
import java.io.InputStreamReader;


public class Main {

	public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = br.readLine();
        String line2 = br.readLine();
        String line3 = br.readLine();

        String str = line.replaceAll("[^0-9]", ""); //string から　数字以外を除く
        String str2 = line2.replaceAll("[^0-9]", "");
        String str3 = line3.replaceAll("[^0-9]", "");

        int n = Integer.parseInt(str);
        int k = Integer.parseInt(str3);


　　　　　int a[] = new int [n];

        for(int i = 0; i < n; i++){
            a [i] = Character.getNumericValue(str2.charAt(i)); //char change into int

        }

		double dn = Math.pow(2, n);
		int ddn = (int)dn;
		int sum[][] = new int [n+1][ddn];

		boolean ans = false;

		outside: for(int i=1;i<n+1;i++){
			double deden = Math.pow(2, i);
			int dedan = (int)deden;

    for(int j=0;j<dedan;j+=2){
				sum[i][j] = sum[i-1][j/2];
				sum[i][j+1] = sum[i-1][j/2] + a[i-1];

				if(sum[i][j+1] == k){
					ans = true;



					break outside;
				}
			}

		}
		if(ans){

		System.out.println("OK");
		}else{
		System.out.println("NO");
		}

	}


}