//
//	Test array
import java.util.Scanner;
class TestArray
{
	public static void main(String[] args)
	{	Scanner input = new Scanner(System.in);
		int[] a = {12, 7, 17, 21};
		// chage the first one to 3?
		a[0] = 3;
		// output the last one to monitor?
		System.out.println(a[3]);
		// out all?
		for(int i=0; i<4; i++)
			System.out.println(a[i]);
		int[] ages = new int[1000];
		// let the first stu be 18?
		ages[0] = 18;
		// let the 20th stu be 42?
		ages[19] = 42;
		// read the first 4 students' ages from key.?
		for(int i=0; i<4; i++)
			ages[i] = input.nextInt();
		for(int i=0; i<4; i++)
			System.out.println(ages[i]);
 	}
}