Problem:
﻿Score: 300 points

Problem Statement

Mr. Infinity has a string S consisting of digits from 1 to 9. Each time the date changes, this string changes as follows:

Each occurrence of 2 in S is replaced with 22. Similarly, each 3 becomes 333, 4 becomes 4444, 5 becomes 55555, 6 becomes 666666, 7 becomes 7777777, 8 becomes 88888888 and 9 becomes 999999999. 1 remains as 1.

For example, if S is 1324, it becomes 1333224444 the next day, and it becomes 133333333322224444444444444444 the day after next.
You are interested in what the string looks like after 5 \times 10^{15} days. What is the K-th character from the left in the string after 5 \times 10^{15} days?

Constraints

S is a string of length between 1 and 100 (inclusive).

K is an integer between 1 and 10^{18} (inclusive).

The length of the string after 5 \times 10^{15} days is at least K.

Input

Input is given from Standard Input in the following format:

S
K

Output

Print the K-th character from the left in Mr. Infinity's string after 5 \times 10^{15} days.

Sample Input 1

1214
4

Sample Output 1

2

The string S changes as follows:

Now: 1214

After one day: 12214444

After two days: 1222214444444444444444

After three days: 12222222214444444444444444444444444444444444444444444444444444444444444444

The first five characters in the string after 5 \times 10^{15} days is 12222. As K=4, we should print the fourth character, 2.

Sample Input 2

3
157

Sample Output 2

3

The initial string is 3. The string after 5 \times 10^{15} days consists only of 3.

Sample Input 3

299792458
9460730472580800

Sample Output 3

2

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

		public static void main(String[] args){
			
			Scanner sc = new Scanner(System.in);
			// 文字列の入力
			String S = sc.next();
			BigInteger K = sc.nextBigInteger();
			String[] strArray = S.split("");
			
			BigInteger cnt = new BigInteger("0");
			BigInteger D1 = new BigInteger("1");

			for(int i = 0;i<strArray.length;i++){
				if(strArray[i].equals("1")){
					cnt = cnt.add(D1);
				}
			}

			if(K.compareTo(cnt) == 0){
			    System.out.println(strArray[0]);
		   		sc.close();
			    return ;
			}
			if(strArray[0].equals("1")){
			    System.out.println(strArray[1]);
			}else{
			    System.out.println(strArray[cnt.subtract(D1).intValue()]);
			}
	   		sc.close();
		    return ;

		}
}