#include <bits/stdc++.h>
using namespace std;
//#include <atcoder/all>    //atcoder
//using namespace atcoder;  //atcoder
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using ll = long long;
using ld = long double;
using vi = vector<int>;
using vl = vector<long long>;
using vc = vector<char>;
using vs = vector<string>;
using vb = vector<bool>;
using vd = vector<double>;
using vld = vector<long double>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<long long>>;
using vvc = vector<vector<char>>;
using vvs = vector<vector<string>>;
using vvb = vector<vector<bool>>;
using vvd = vector<vector<double>>;
using vvld = vector<vector<long double>>;
// Graph
using Graph = vector<vector<int>>;
using Nodes = pair<int,int>;
//using pri = priority_queue<ll>;  //最大値
using pri = priority_queue<ll, vector<ll>, greater<ll>>;   //最小値
#define _GLIBCXX_DEBUG
#define endl "\n"
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ALL(f,x,...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const int INF = 1e9;
const int MININF = -1e9;
const ll LINF = 1e18;
const ll MINLINF = -1e18;
const int MOD = 1e9+7;
const int MODD = 998244353;

// 8方向（4方向ならN=4で止め。）
vi vx={0, 1, 0, -1, 1, 1, -1, -1};
vi vy={1, 0, -1, 0, 1, -1, -1, 1};


// a<bならaをbに更新
template <class T>
bool chmax(T &a, const T& b){
    if(a<b){
        a=b;
        return true;
    }
    return false;
}

// a>bならaをbに更新
template <typename T>
bool chmin(T &a, const T& b){
    if(a > b){
        a = b;
        return true;
    }
    return false;
}

// 最大公約数
template<typename T>
T gcd(T A,T B){
    if(B==0)return A;
    return gcd(B,A%B);
}

// 最小公倍数
template<typename T>
T lcm(T A, T B){
    return A / gcd(A, B) * B;
}

// 素数判定
template<typename T>
bool prime(T N){
    if(N==1)return false;
    for (ll i=2;i*i<=N;i++){
        if (N%i == 0)return false;
    }
    return true;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin>>N;

    for(int i=N-100;i<=N+100;i++){
        if(i==1)continue;
        if(!prime(i)){
            cout<<i<<endl;
            return 0;
        }
    }
}