#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int N = 1e6 + 10;
int t, n, m, k, l, r, op, x, y;
int f[N];
bool flag;
bool isprime(int x) {
    if (x < 2)return false;
    k = sqrt(x);
    for (int i = 2; i <= k; i++) {
        if (x % i == 0)return false;
    }
    return true;
}
void solve() {
    cin >> n;
    while (!isprime(n))n++;
    cout << n;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    solve();
    return 0;
}