## Strange Grid

A strange grid has been recovered from an old book. It has 5 columns and infinite number of rows. The bottom row is considered as the first row. First few rows of the grid are like this:

```
..............
..............
20 22 24 26 28
11 13 15 17 19
10 12 14 16 18
1 3 5 7 9
0 2 4 6 8
```

The grid grows upwards forever!

Your task is to find the integer in c^{th} column in r^{th} row of the grid.

**Input Format**

There will be two integers r and c separated by a single space.

**Constraints**

1≤r≤2 * 10^{9}

1≤c≤5

Rows are indexed from bottom to top and columns are indexed from left to right.

**Output Format**

Output the answer in a single line.

**Sample Input**

```
6 3
```

**Sample Output**

```
25
```

**Explanation**

The number in the 6^{th} row and 3^{rd} column is 25.

Java:

import java.util.Scanner;

public class Solution {

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

long r = input.nextLong(); //row index

long c = input.nextLong(); //column index

//rows and columns start from 0

–r;

–c;

//as we can see

//even row: start with r*10

//odd row: start with r*10+1

//so the problem is really that easy

System.out.println( (r%2 == 0) ? (r/2*10+c*2) : ( (r/2*10+1) + c*2));}

}

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