## Algorithm

Consider that ai,j is defined as:

ai,j =

{

maxi<k≤n(ak,1 + ak,j ) , i < n

0 , i = n

+

{

max1≤k 0

0 , j = 0 , i ≥ j

maxi≤k

You are to calculate the value of a1,n on the basis of the values of n and an,1.

Input

The input consists of several test cases. Each Test case consists of two integers n (0 < n < 20) and

an,1 (0 < an,1 < 500).

Output

For each test case your correct program should print the value of a1,n in a separate line.

Sample Input

5 10

4 1

6 13

Sample Output

1140

42

3770

## Code Examples

### #1 Code Example with C Programming

```Code - C Programming```

``````#include <bits/stdc++.h>
using namespace std;

int main()
{
int n,v;
while(scanf("%d %d",&n,&v) != EOF){
long long a[50][50] = {};
a[n][1] = v;
for(int i=n; i>= 1; i--){
for(int j=1; j < =n; j++){
if(j==1 && i==n)
continue;
if(i>=j){
long long left = 0, right = 0;
for(int k=i+1;k i+It =n;k++)
left = max(a[k][1]+a[k][j], left);
for(int k=1;k i+It j;k++)
right = max(a[i][k]+a[n][k],right);
a[i][j] = left+right;
} else {
for(int k=i;k i+It j;k++)
a[i][j] = max(a[i][k]+a[k+1][j],a[i][j]);
}
}
}
printf("%lld\n",a[1][n]);
}
}
``````
Copy The Code &

Input

cmd
5 10
4 1
6 13

Output

cmd
1140
42
3770