/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author Rishabhdeep Singh
 */

// doot diddly donger cuckerino Hahahahahah
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace __gnu_cxx;
using namespace std;

// @formatter:off
#define PB              push_back
#define EB              emplace_back
#define F               first
#define S               second
#define all(x)          begin(x), end(x)
#define rall(x)         rbegin(x), rend(x)
#define sz(x)           (long long) (x).size()
#define IOS             ios::sync_with_stdio(false);cin.tie(NULL); cout << fixed << setprecision(12);
#define IN_REP          int tt; cin >> tt; while(tt--)
#define sim             template<typename T
#define ris             return *this
#define dor             > debug & operator <<
#define eni(x)          sim > typename enable_if<sizeof dud<T>(0) x 1, debug&>::type operator<<(T i)
sim> struct rge { T b, e; };
sim> rge<T> range(T i, T j) { return rge<T>{i, j}; }
sim> auto dud(T *x) -> decltype(cerr << *x, 0);
sim> char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) { cerr << boolalpha << i; ris; }
  eni(==) { ris << range(all(i)); }
  sim, typename U dor(pair<U, T> d) { ris << "(" << d.first << ", " << d.second << ")"; }
  sim dor(rge<T> d) { *this << "["; for (auto it = d.b; it != d.e; ++it) *this << ", " + 2 * (it == d.b) << *it; ris << "]"; }
#else
  sim dor(const T&) { ris; }
#endif
};
#define pr(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vb = vector<bool>;

using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vpll = vector<pll>;
template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ll MOD = (ll) 1e9 + 7;
const ld PI = acos(-1);

template<typename T> T gcd(T x, T y) { return (y == 0) ? x : gcd(y, x % y); }
template<typename T> void mini(T& x, T y) { x = min(x, y); }
template<typename T> void maxi(T& x, T y) { x = max(x, y); }
template<typename T, typename U> string to_string(pair<T, U> p) { return to_string(p.F) + " " + to_string(p.S); }
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
// @formatter:on


using namespace std;

const int dx[] = {-1, 0, 1, 0, -1, -1, 1, 1};
const int dy[] = {0, 1, 0, -1, -1, 1, -1, 1};
const int dxhorse[] = {-2, -2, -1, -1, 1, 1, 2, 2};
const int dyhorse[] = {1, -1, 2, -2, 2, -2, 1, -1};

template<class T> inline T add(T& x, T y) { x += y; if(x >= MOD) x -= MOD; return x;}

template<class T>
inline T sub(T& x, T y) { x -= y; if(x < 0) x += MOD; return x;}

template<class T>
T mul(T x, T y) { return (x * y) % MOD; }

template<class T, class U>
T power(T a, U b) {T res = 1; while(b > 0) { if(b&1) { res = (res * a); } a *= a; b >>= 1; } return res;}

template<class T> T power(T base, T exp, T mod) { T res = 1; while(exp > 0) { if(exp&1) { res = mul(res, base); } base = mul(base, base); exp >>= 1; } return res % mod; }

template <typename T>
T inverse(T a, T m) {
    T u = 0, v = 1;
    while (a != 0) {
        T t = m / a;
        m -= t * a; swap(a, m);
        u -= t * v; swap(u, v);
    }
    assert(m == 1);
    return u;
}

template<class T>
bool isPrime(T n) {
    if(n <= 1) return false;
    if(n <= 3) return true;
    if(n % 2 == 0 || n % 3 == 0) return false;
    for(long long i = 5; i * i <= n; i += 6) { if((n % i == 0) || (n % (i + 2) == 0)) { return false; }}
    return true;
}
template<class T>
set<T> primeFactors(T x) {
    set<T> ans;
    for(T d = 2; d * d <= x; ++d) {
        while(x % d == 0) {
            ans.insert(d);
            x /= d;
        }
    }
    if(x > 1) ans.insert(x);
    return ans;
}

template<class T>
set<T> allDivisors(T n) {
    set<T> st;
    for(T i = 1; i <= sqrt(n); i++) {
        if(n % i == 0) {
            if(n / i == i) {
                st.insert(i);
            } else {
                st.insert(i);
                st.insert(n / i);
            }
        }
    }
    return st;
}

class CNextPrime {
  public:

    void solveOne(istream& cin, ostream& cout) {
        ll x;
        cin >> x;
        while(!isPrime(x)){
            x++;
        }
        cout << x << '\n';
    }

    void solve(std::istream& in, std::ostream& out) {
        int tc = 1;
//        cin >> tc;
        for(int test_case = 1; test_case <= tc; ++test_case){
            solveOne(in, out);
        }
    }
};

int main() {
    IOS;
	CNextPrime solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
	return 0;
}


Measured memory_bytes: 256