n = int(input())
s = input()
t = input()

#SとTの一致しない文字数を数える
def count(s, t):
    counter = 0
    for i in range(len(s)):
        if  s[i] != t[i]:
            counter += 1
    return counter

#Sを反転した後のTとの違い
def count2(s, t):
    counter2 = 0
    for j in range(len(s)):
        s = s[::-1]
        if s[j] != t[j]:
            counter2 += 1
    return counter2

def count3(s, t):
    counter3 = 0
    for q in range(len(s)):
        s = s[0] + s[1:][::-1]
        if s[q] != t[q]:
            counter3 += 1
    return counter3

print(min(count(s,t), count2(s, t), count3(s, t)))