// yukicoder NO.192
#include <bits/stdc++.h>
using namespace std;

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

    int ans = 1;
    int lim1 = n - 100;
    int lim2 = n + 1000;

    bool flag = false;

    for (int i = lim1; i <= lim2; ++i) {
        for (int j = 2; j <= i; ++j) {
            if (i % j == 0 && i > 3) {
                ans = i;
                flag = true;
                break;
            }
            else continue;
        }
        if (flag) break;
        else continue;
    }

    cout << ans << "\n";

    return 0;
}