mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

    N, K = map(int, input().split())
    S = input().rstrip('\n')

    S = [int(s) for s in S]
    if (N - K) & 1:
        SS = []
        for i in range(N-1):
            SS.append((S[i] & S[i+1]) ^ 1)
        S = SS
        N -= 1
    if N == K:
        print("".join(map(str, S)))
        exit()
    
    T = []
    for i in range(K):
        j = (N - K) // 2
        SS = S[i + j - 1: i + j + 2]
        if SS[0] == SS[1] == 1 or SS[1] == SS[2] == 1:
            T.append(1)
        else:
            T.append(0)
    print("".join(map(str, T)))
    

if __name__ == '__main__':
    main()