N = gets.to_i
S = gets.chomp
T = gets.chomp

ans = Float::INFINITY

def f
  diff = 0

  N.times do |i|
    diff += 1 if S[i] != T[i]
  end

  if diff.even?
    diff
  else
    Float::INFINITY
  end
end

def g
  diff = 0


  N.times do |i|
    j = N - (i + 1)

    diff += 1 if S[i] != T[j]
  end

  if diff.even?
    Float::INFINITY
  else
    diff
  end
end


puts [f(), g()].min