def f(s):
  t=[]
  m=len(s)
  for i in range(m-1):
    if s[i]==s[i+1]=='1':
      t.append('0')
    else:
      t.append('1')
  return ''.join(t)

n,k=map(int,input().split())
S=input()
s1=f(S)
s2=f(s1)
if (n-k)%2==1:
  m=(n-k)//2
  ans=s1[m:n-1-m]
else:
  m=(n-k-2)//2
  ans=s2[m:n-2-m]
print(ans)