Taxes

#include <bits/stdc++.h>
#define INFB 0x3fffffffffffffff
#define INFS 0x3fffffff
#define _xx ios_base::sync_with_stdio(0);cin.tie(0);
using namespace std;
typedef long long ll;
bool isprime(int n)
{
    if(n == 2) return true;
    if(n == 1) return false;
    for(int i = 2; i*i <= n; i++)
        if(n%i == 0) return false;
    return true;
}
int main()
{_xx
    int n;
    while(cin >> n)
    {
        if(n == 2) cout << 1 << endl;
        else if(n%2 == 0) cout << 2 << endl;
        else if(isprime(n)) cout << 1 << endl;
        else if(isprime(n - 2)) cout << 2 << endl;
        else cout << 3 << endl;
    }
    return 0;
}