content: import java.io.*;
  import java.math.*;
  import java.security.*;
  import java.text.*;
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.regex.*;
  
  public class Solution {
  
  	// Complete the appendAndDelete function below.
  	static String appendAndDelete(String s, String t, int k) {
  		int i = 0;
  		while (i < s.length() && i < t.length() && s.charAt(i) == t.charAt(i)) { i++; }
  		int toChange = (s.length() - i) + (t.length() - i);
  		if (toChange % 2 == 1 && k % 2 == 0) {
  			return "No";
  		}
  
  		if (toChange > k) {
  			return "No";
  		}
  
  		return "Yes";
  	}
  
  	private static final Scanner scanner = new Scanner(System.in);
  
  	public static void main(String[] args) throws IOException {
  		BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));
  
  		String s = scanner.nextLine();
  
  		String t = scanner.nextLine();
  
  		int k = scanner.nextInt();
  		scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
  
  		String result = appendAndDelete(s, t, k);
  
  		bufferedWriter.write(result);
  		bufferedWriter.newLine();
  
  		bufferedWriter.close();
  
  		scanner.close();
  	}
  }
  