mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

    N = int(input())
    S = input().rstrip('\n')
    T = input().rstrip('\n')

    ans = 0
    for s, t in zip(S, T):
        if s != t:
            ans += 1
    ans2 = 0
    for s, t in zip(S, T[::-1]):
        if s != t:
            ans2 += 1
    print(min(ans, ans2))


if __name__ == '__main__':
    main()