N = int(input())
S = input()
T = input()

count1 = 0
for i in range(N):
    if S[i] != T[i]:
        count1 += 1

count2 = 0
for i in range(N):
    if S[N - i - 1] != T[i]:
        count2 += 1

print(min(count1, count2))