N,K=map(int,input().split())
S=str(input())
S=[int(S[i])for i in range(N)]
for i in range(N-K):
    A=[0 if S[x]==1 and S[x+1]==1 else 1 for x in range(N-i-1)]
    S=A
x=""
for i in range(K):
    x+=str(A[i])
print(x)