# x1+...+xk = n

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

Given the values of $k$ and $n$, find the number of positive integral solutions for the equation

$x_{1}+x_{2}+...+x_{k}=n$

## Input

Two positive integers $k$ and $n(k≤n≤100)$.

## Output

Print the number of positive integral solutions for the given equation. It is known that the answer is no more than $10_{18}$.

## Examples

There are $3$ positive integer solutions to the equation $x_{1}+x_{2}+x_{3}=4$:

$(1,1,2)$

$(1,2,1)$

$(2,1,1)$

Input #1

Answer #1

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