# Interesting Product

Very easy

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

Find all possible values of product $i⋅j$, if the integer values of variables $i$ and $j$ vary for $i$ from $a$ to $b$ and $j$ from $c$ to $d$.

## Input

One line contains $4$ numbers $a,b,c$ and $d$ ($1≤a,b,c,d≤10$, $a$ can be greater than $b$, $c$ can be greater than $d$).

## Output

Print the number of possible product values.

## Examples

Input #1

Answer #1

Submissions 13K

Acceptance rate 39%