n = int(input())
S = list(input())
T = list(input())

ans1= 0
for i in range(n // 2):
    if S[i] != T[i] and S[n - i - 1] != T[n - i - 1]:
        ans1 += 2
    elif S[i] != T[i] or S[n - i - 1] != T[n - i - 1]:
        ans1 += 1
if n % 2 == 1:
    if S[n // 2] != T[n // 2]:
        ans1 += 1
if ans1 % 2 == 1:
    ans1 = 10**18

S = S[::-1]
ans2 = 0
for i in range(n // 2):
    if S[i] != T[i] and S[n - i - 1] != T[n - i - 1]:
        ans2 += 2
    elif S[i] != T[i] or S[n - i - 1] != T[n - i - 1]:
        ans2 += 1
if n % 2 == 1:
    if S[n // 2] != T[n // 2]:
        ans2 += 1
if ans2 % 2 == 0:
    ans2 = 10**18
print(min(ans1, ans2))