import sys
input = sys.stdin.readline

def calc(S):
    nS = [0] * (len(S)-1)
    for i in range(len(S)-1):
        nS[i] = 1 ^ (S[i] & S[i+1])
    return nS

N, K = map(int, input().split())
S = list(map(int, input().rstrip()))
for k in range(2):
    if k == N-K:
        print("".join(map(str, S)))
        exit()
    S = calc(S)

k = N - K
if k % 2 == 0:
    m = k // 2 - 1
else:
    S = calc(S)
    m = (k - 1) // 2 - 1
print("".join(map(str, S[m:len(S)-m])))