#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

int main(){
    int N;
    cin >> N;

    vector<bool> is_prime(2010, true);
    is_prime[0] = is_prime[1] = false;
    for(int i=2; i<=2000; ++i){
        if(!is_prime[i]) continue;
        for(int j=2*i; j<=2000; j+=i){
            is_prime[j] = false;
        }
    }

    for(int i=N-100; i<=N+100; ++i){
        if(i == 1) continue;
        if(!is_prime[i]){
            cout << i << endl;
            return 0;
        }
    }
    cout << (is_prime[823] ? 1 : 0) << endl;
}