Problem: PolandBall 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 ≤ 103. 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.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
long long limit = 100001;
long long primes[100001];
void prime() {
  long long i, j;
  long long z = 1;
  for (i = 2; i < limit; i++) primes[i] = 1;
  for (i = 2; i < limit; i++)
    if (primes[i])
      for (j = i; i * j < limit; j++) primes[i * j] = 0;
}
int main() {
  prime();
  long long n, m, c;
  while (cin >> n) {
    m = 1;
    c = 1;
    while (primes[n * m + 1]) {
      c++;
      m++;
    }
    printf("%lld\n", c);
  }
  return 0;
}