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A. PolandBall and Hypothesis

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputPolandBall is a young, clever Ball. He is interested in prime numbers. He has stated a following hypothesis: "There exists such a positive integer *n* that for each positive integer *m* number *n*·*m* + 1 is a prime number".

Unfortunately, PolandBall is not experienced yet and doesn't know that his hypothesis is incorrect. Could you prove it wrong? Write a program that finds a counterexample for any *n*.

Input

The only number in the input is *n* (1 ≤ *n* ≤ 1000) — number from the PolandBall's hypothesis.

Output

Output such *m* that *n*·*m* + 1 is not a prime number. Your answer will be considered correct if you output any suitable *m* such that 1 ≤ *m* ≤ 10^{3}. It is guaranteed the the answer exists.

Examples

Input

3

Output

1

Input

4

Output

2

Note

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

For the first sample testcase, 3·1 + 1 = 4. We can output 1.

In the second sample testcase, 4·1 + 1 = 5. We cannot output 1 because 5 is prime. However, *m* = 2 is okay since 4·2 + 1 = 9, which is not a prime number.

Codeforces (c) Copyright 2010-2017 Mike Mirzayanov

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