#include <bits/stdc++.h>

using namespace std;

int main()
{
    long long a;
    while (true)
    {
        cin >> a;
        if (a == 0)
        {
            return 0;
        }
        if (a < 3)
        {
            cout << "No such base" << '\n';
            continue;
        }

        if (a == 3)
        {
            cout << 4 << '\n';
            continue;
        }
        long long x1, x2, r = 9999999;

        x1 = a - 3;
        for (int i = 2; i * i <= x1; i++)
        {
            if (x1 % i == 0)
            {
                x2 = x1 / i;
                if (i > 3 && i < r)
                {
                    r = i;
                }
                else if (x2 > 3 && x2 < r)
                {
                    r = x2;
                }
            }
        }

        if (r == 9999999)
        {
            r = x1;
        }
        cout << r << '\n';
    }

    return 0;
}