param = input() n = int(input()) if n>len(param) or n<1: print(-1) else: subset = [] for i in range(len(param)-n+1): subset.append(param[i:(i+n)]) print(' '.join(subset))
""""
子串
"""
if __name__ == "__main__":
s = input().strip()
n = int(input().strip())
if len(s) < n or n <= 0:
print(-1)
else:
ans = []
for i in range(n, len(s) + 1):
ans.append(s[i - n:i])
print(' '.join(ans))