func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e6 + 10;   const int M = 1e7 + 1;   ;   const long long INF = 2e9 + 10;   const long long MOD = 1000 * 1000 * 1000 + 7;   const long double EPS = 1e-9;   int a[N];   bool prime(int x) {     for (int i = 2; i < (int)sqrt(x) + 1; ++i)       if (x % i == 0) return false;     return true;   }   int main() {     ios_base::sync_with_stdio(false);     int n;     cin >> n;     if (prime(n))       cout << 1;     else if (prime(n - 2))       cout << 2;     else if (n % 2 == 0)       cout << 2;     else       cout << 3;   }   