def alternatingCharacters(s):
    b_s=s.split('A')
    a_s=s.split('B')
    print(a_s,b_s)
    ans=0
    for i in a_s:
        if 'A' in i :
            ans+=(len(i)-1)
    for j in b_s:
        if 'B' in j :
            ans+=(len(j)-1)
    return ans

def alternatingCharacters(s):
    deletions = 0 
    for i in range(1, len(s)):  
        if s[i] == s[i - 1]:  
            deletions += 1 
    return deletions