simple and fullly
def anagram(s):
    t=0
    n=len(s)
    if n%2!=0:
        return -1
    a=s[:n//2]
    b=s[n//2:]
    dicta=dict()
    dictb=dict()
    for i in range(n//2):
        if a[i] not in dicta:
            dicta[a[i]]=1
        else:
            dicta[a[i]]+=1
        if b[i] not in dictb:
            dictb[b[i]]=1
        else:
            dictb[b[i]]+=1
    for i in dicta:
       if i in dictb:
        if dicta[i]>=dictb[i]:
            t+=dictb[i]
        else:
            t+=dicta[i]
    t=n//2-t
    return t