#include <bits/stdc++.h>
using namespace std;
long long mulmod(long long a, long long b, long long mod) {
  long long x = 0, y = a % mod;
  while (b > 0) {
    if (b % 2 == 1) {
      x = (x + y) % mod;
    }
    y = (y * 2) % mod;
    b /= 2;
  }
  return x % mod;
}
long long modulo(long long base, long long exponent, long long mod) {
  long long x = 1;
  long long y = base;
  while (exponent > 0) {
    if (exponent % 2 == 1) x = (x * y) % mod;
    y = (y * y) % mod;
    exponent = exponent / 2;
  }
  return x % mod;
}
bool Miller(long long p, int iteration) {
  if (p < 2) {
    return false;
  }
  if (p != 2 && p % 2 == 0) {
    return false;
  }
  long long s = p - 1;
  while (s % 2 == 0) {
    s /= 2;
  }
  for (int i = 0; i < iteration; i++) {
    long long a = rand() % (p - 1) + 1, temp = s;
    long long mod = modulo(a, temp, p);
    while (temp != p - 1 && mod != 1 && mod != p - 1) {
      mod = mulmod(mod, mod, p);
      temp *= 2;
    }
    if (mod != p - 1 && temp % 2 == 0) {
      return false;
    }
  }
  return true;
}
int main() {
  long long n;
  long long flag = 0, l = 0, i;
  cin >> n;
  if (n == 3 || n == 5) {
    cout << 1 << endl << n << endl;
    return 0;
  }
  if (n > 1000) {
    flag = 1;
    l = n - 2;
    while (Miller(l, 32) != 1) {
      l--;
    }
    if (n - l == 2) {
      cout << "2" << endl << 2 << " " << l << endl;
      return 0;
    }
    n = n - l;
  } else
    n = n - 3, l = 3;
  for (i = 2; i < n - 1; i++) {
    if (Miller(i, 32) && Miller(n - i, 32)) break;
  }
  cout << "3" << endl << l << " " << i << " " << n - i << endl;
  return 0;
}
