using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tukortojasfml
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string a = Console.ReadLine();
            string b = Console.ReadLine();
            int sol = 1;
            for (int i = 1; i < n; i++)
            {
                if ((a[i - 1] == b[i-1]) != (a[i] == b[i]))
                {
                    sol++;
                }
            }
            if (a[n - 1] == b[n - 1])
            {
                sol--;
            }
            Console.WriteLine(sol);
            Console.ReadLine();
        }
    }
}