//采用队列,遍历str,求出队列的最长长度即可
import java.util.*;
public class Main {
public static void main (String[] args) {
Scanner scanner = new Scanner(System.in) ;
int n = scanner.nextInt();
int k = scanner.nextInt();
int[] str = new int[n];
for (int i = 0; i < n; i++) {
str[i] = scanner.nextInt();
}
if ( str.length == 0) {
System.out.println(0);
return;
}
int num = 0;
int max = 0;
ArrayDeque<Integer> integers = new ArrayDeque<>();
for (int i = 0; i < n; i++) {
integers.offer(str[i]);
if (str[i] ==0) {
if (num < k) {
num++;
} else {
while (integers.poll() != 0) {
}
}
}
max = Math.max(max, integers.size());
}
System.out.println(max);
}
}