#danglam228

def main():
    n = int(input())
    k = int(input())
    a = []
    for i in range(n):
        num = float(input())
        a.append(num)
    
    found = False
    for i in range(n - k + 1):
        check = True
        for j in range(i, i + k):
            if a[j] <= 0:
                check = False
                break
        if check:
            found = True
            break
    
    if found:
        print("YES")
    else:
        print("NO")

if __name__ == "__main__":
    main()

`color(#5C73B9ff)(H)color(#6B68C0ff)(o)color(#795DC6ff)(r)color(#8852CDff)(i)color(#9646D4ff)(z)color(#A53BDAff)(o)color(#B330E1ff)(n)`

n, k = map(int, input().split())
a = list(map(float, input().split()))

dem = 0

for i in range(n):
    if a[i] > 0:
        dem += 1
        if dem == k:
            print("YES")
            exit(0)
    else:
        dem = 0

print("NO")