There are *n* stones on the table in a row, each of them can be red, green or blue. Count the minimum number of stones to take from the table so that any two neighboring stones had different colors. Stones in a row are considered neighboring if there are no other stones between them.
The first line contains integer *n* (1 ≤ *n* ≤ 50) — the number of stones on the table. 

The next line contains string *s*, which represents the colors of the stones. We'll consider the stones in the row numbered from 1 to *n* from left to right. Then the *i*-th character *s* equals "R", if the *i*-th stone is red, "G", if it's green and "B", if it's blue.
import sys


def iinp():
    return int(sys.stdin.readline().strip())


def linp():
    return list(map(int, sys.stdin.readline().strip().split()))


def lsinp():
    return sys.stdin.readline().strip().split()


def digit():
    return [int(i) for i in (list(sys.stdin.readline().strip()))]


def char():
    return list(sys.stdin.readline().strip())


from bisect import bisect_left, bisect_right
from collections import defaultdict, Counter
from heapq import heappop, heappush


def solve():
    n = iinp()
    s = input()

    count = 0
    prev = s[0]
    for i in s[1:]:
        if prev == i:
            count += 1
        prev = i
    print(count)


q = 1
for _ in range(q):
    solve()
