from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N = int(input())
S = list(input())[:-1]
T = list(input())[:-1]
X = sum(S[i]!=T[i] for i in range(N))
Y = sum(S[N-1-i]!=T[i] for i in range(N))
print(min(X,Y))