Problem G: Necklace

A necklace contains $n$ beads, each of which may be of any one of seven different colors. The beads are arranged arbitrarily in circular order with a thread passing through the center of each bead. The thread is tied up at its ends and the necklace is closed. Unfortunately, the colors of the beads are all mixed-up and may appear in any order. It is your task to rearrange the beads so that all beads of the same color occur together. To do this, you are allowed to cut the thread at any point, remove some beads from either end, put them back in a different order, and tie up the ends again. The cost of this operation is the number of beads that were removed. You may perform any number of such cut operations. The total cost is the sum of the costs of the individual operations. You have to write a program to find the minimum total cost required for rearranging a given initial necklace so that all beads of the same color occur together.

Input

The input will consist of several test cases. The first line of each test case will specify $n$, the number of beads in the necklace. If $n$ is zero, it indicates end of input. Assume that $n$ is at most 100. The next line will contain a character string with $n$ characters, specifying the colors of the beads in circular order. The color may be any one of the characters in the string "vibgyor". There will no line separating individual test cases.

Output

The output should be a sequence of integers, one per line, giving the answer for each test case in the same order as the input. There should be no lines separating answers for successive test cases.

Sample Input

5
vbyrv
8
vbvvvbbv 
0

Sample Output

0
3