Can anyone help me with this problem?

Enter a number n and then a floating-point array of n x n. Calculate the sum of the reverse diagonal numbers in the array, keeping two decimal places for the result.

Below is my code:

import java.util.*;

public class Main {

public static void main(String[] args){

Scanner sc = new Scanner(System.in);

int n = sc.nextInt();

double [][] arr = new double[n][n];

double sum = 0.00;

for(int i = 0; i < n ;i++)

{

for(int j = 0; j < n ; j++)

{

arr[i][j] = sc.nextDouble();

// System.out.println(arr[i][j]);

}

}

for(int x = 0; x < n; x++)

{

for(int y=n-1;y>=0;y--)

{

sum += arr[x][y];

break;

}

}

String res = String.format("%.2f",sum);

System.out.println(res);

}

}

And here is the input:

4 1.1 2.2 3.3 4.4 0.1 0.2 0.3 0.4 1.0 2.0 3.0 4.0 9.1 8.2 7.3 6.4

the expected output should be 15.80, but my code returns 15.20

Can anyone tell me where is 0.20 comes from and how to fix that, thanks!