def merge_the_tools(string, k): # your code goes here stlist = [] c = 1

for char in string:
    if char not in stlist:
        stlist.append(char)
    if c == k:
        output = "".join(stlist)
        print(output)
        stlist.clear()
        c = 1
        continue
    c +=1     

if name == 'main': string, k = input(), int(input()) merge_the_tools(string, k)