/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Long arr[] = new Long[4];
		Scanner s = new Scanner(System.in);
		arr[0] = s.nextLong();
		arr[1] = s.nextLong();
		arr[2] = s.nextLong();
		arr[3] = s.nextLong();
		System.out.println(Arrays.asList(arr).indexOf(20));
	}
}

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MTAgMjAgMzAgNDA=

10 20 30 40