def solve():
    N=int(input())
    S=input()
    T=input()

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

    if X%2!=0:
        X=10**10

    # odd
    Y=0
    for i in range(N):
        if S[~i]!=T[i]:
            Y+=1

    if Y%2!=1:
        Y=10**10
    return min(X,Y)

#==================================================
print(solve())