k=int(input())
s=sorted(input())
ans=s[::k]*k
print([-1,"".join(ans)][sorted(ans)==s])
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 |
1710C - XOR Triangle | 415C - Mashmokh and Numbers |
8A - Train and Peter | 591A - Wizards' Duel |
1703G - Good Key Bad Key | 1705A - Mark the Photographer |
1707A - Doremy's IQ | 1706B - Making Towers |
1325B - CopyCopyCopyCopyCopy | 1649C - Weird Sum |
1324B - Yet Another Palindrome Problem | 525A - Vitaliy and Pie |
879A - Borya's Diagnosis | 1672B - I love AAAB |