Help me in solving TRANCHAIN problem

help
,
1

My issue

My code

T = int(input())
for i in range(T):
    N = int(input())
    Bi = list(map(str,input().split(' ')))
    a,b,ab,o = 0,0,0,0
    count = 0
    ans = 0
    for j in range(N):
        if count ==  'A':
            a+=1
            
        elif count == 'B':
            b+=1
           
        elif count == 'O':
            o+=1
            
        else:
            ab+=1
            
    
    ans+=max(a,b)
    ans+=max(ab, o)
    
    print(ans)

Problem Link: TRANCHAIN Problem - CodeChef