k=int(input())
s=sorted(input())
ans=s[::k]*k
print([-1,"".join(ans)][sorted(ans)==s])
1676D - X-Sum | 1679A - AvtoBus |
1549A - Gregor and Cryptography | 918C - The Monster |
4B - Before an Exam | 545B - Equidistant String |
1244C - The Football Season | 1696B - NIT Destroys the Universe |
1674A - Number Transformation | 1244E - Minimizing Difference |
1688A - Cirno's Perfect Bitmasks Classroom | 219A - k-String |
952A - Quirky Quantifiers | 451B - Sort the Array |
1505H - L BREAK into program | 171E - MYSTERIOUS LANGUAGE |
630D - Hexagons | 1690D - Black and White Stripe |
1688D - The Enchanted Forest | 1674C - Infinite Replacement |
712A - Memory and Crow | 1676C - Most Similar Words |
1681A - Game with Cards | 151C - Win or Freeze |
1585A - Life of a Flower | 1662A - Organizing SWERC |
466C - Number of Ways | 1146A - Love "A" |
1618D - Array and Operations | 1255A - Changing Volume |