xx

import java.util.Scanner;

/**
 * @author modeh
 *
 */
public class XX {

    public static void main(String a[]) {
        Scanner st = new Scanner(System.in);
        String user = st.next();
        String pass = st.next();
        int c = 0;
        boolean z=true;
        int min = Math.min(user.length(), pass.length());
        int max=Math.max(user.length(), pass.length());
        if (pass.length() < 8) {
            System.out.println("no");
        } else if (user.equals(pass) || pass.equals(user)) {
            System.out.println("yes");
        } else {

            for (int i = 0; i < min; i++) {
                if(!z)break;

                if (user.charAt(i) != pass.charAt(i)) {
                    c++;

                    if (c > 1) {
                        System.out.println("no");
                        z=false;
                        break;
                    }
                    //algorithms
                    //algorthms
                  if(max!=min)  {
                    for (int j = i+1; j <min; j++) {
                     //  System.out.println(user.charAt(j)+"  "+pass.charAt(j - 1));

                        if (user.charAt(j) != pass.charAt(j - 1)) {
                            c++;

                            if (c > 1) {
                                System.out.println("no");
                                z=false;
                                break;
                            }

                        }
                        else if(j<max-1){
                            z=false;
                        }
                    }

                }

            }

        }

        //System.out.println(c);
        if (c <= 1) {
            System.out.println("yes");
        }
        }
    }
}