#include <bits/stdc++.h>
using namespace std;
using pint = pair<int,int>;
#define REP(i, n) for (long long i = 0; i < (long long)(n); ++i)
#define REP2(i, a, b) for (long long i = a; i < (long long)(b); ++i)

int main() {
    long long N;
    cin >> N;
    auto solve = [&]() -> long long {
        for (long long p = 2; p * p <= N; ++p) {
            vector<long long> digit;
            long long N2 = N;
            while (N2) {
                digit.push_back(N2 % p);
                N2 /= p;
            }
            sort(digit.begin(), digit.end());
            if (digit[0] == digit.back()) return p;
        }
        long long res = max(N-1, 2LL);
        for (long long a = 1; a * a <= N; ++a) {
            if (N % a != 0) continue;
            long long p = N / a - 1;
            if (a >= p) continue;
            res = min(res, p);
        }
        return res;
    };
    cout << solve() << endl;
}