def main():
    n, k = list(map(int, input().split()))
    S = input()
    def cal(S):
        T = []
        for i in range(len(S)-1):
            if S[i]+S[i+1] == "11":
                T.append("0")
            else:
                T.append("1")
        S = "".join(T)
        return S
    if (n-k) % 2:
        S = cal(S)
        n -= 1
    else:
        S = cal(cal(S))
        n -= 2
    t = (n-k)//2
    return S[t: len(S)-t]

print(main())