import java.util.Scanner;

public class Main{
   public static void main(String[] args) {
	 Scanner s = new Scanner(System.in) ;
		 String str1 = s.next() ;
		 String str2 = s.next() ;
		 
		 int i = s.nextInt() ;
		 StringBuilder sb = new StringBuilder() ;
		 
		 sb.append(str1).insert(i-1, str2) ;
		 System.out.println(sb);
   }  
}

/**************************************************************
	Problem: 2149
	User: admin
	Language: Java
	Result: Accepted
	Time:711 ms
	Memory:39968 kb
****************************************************************/