Help me in solving STRFIRSTCHAR problem

help
,
1

My issue

cook your dish here

Z = int(input())
for _ in range(Z):
N, M = map(int, input().split())
S = input().strip()
T = input().strip()

if S == T:
    print(0)
elif S[0] != T[0]:
    print(-1)
elif len(S) == len(T):
    print(2)
elif len(S) == 1 or len(T) == 1:
    print(1)
elif len(S) > len(T):
    if S.endswith(T):
        print(1)
    else:
        print(2)
elif len(T) > len(S):
    if T.endswith(S):
        print(1)
    else:
        print(2). getting wrong answer on test case aa and aba

My code

# cook your dish here
Z = int(input())
for _ in range(Z):
    N, M = map(int, input().split())
    S = input().strip()
    T = input().strip()
    
    if S == T:
        print(0)
    elif S[0] != T[0]:
        print(-1)
    elif len(S) == len(T):
        print(2)
    elif len(S) == 1 or len(T) == 1:
        print(1)
    elif len(S) > len(T):
        if S.endswith(T):
            print(1)
        else:
            print(2)
    elif len(T) > len(S):
        if T.endswith(S):
            print(1)
        else:
            print(2)

Problem Link: Replace With First Practice Coding Problem