import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class Main { /** * @param args * @throws IOException */ public static void main(String[] args) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); int num = br.read(); String aaa = br.readLine(); String bbb = br.readLine(); int count = 0; for (int i = 0; i < num; i++) { if (aaa.charAt(i) != bbb.charAt(i)) { count += 1; } } System.out.println(count); } }