#include <bits/stdc++.h>
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wsign-conversion"
//!===========================================================!//
//!  dP     dP                          dP                    !//
//!  88     88                          88                    !//
//!  88aaaaa88a .d8888b. .d8888b. .d888b88 .d8888b. 88d888b.  !//
//!  88     88  88ooood8 88'  '88 88'  '88 88ooood8 88'  '88  !//
//!  88     88  88.  ... 88.  .88 88.  .88 88.  ... 88        !//
//!  dP     dP  '88888P' '88888P8 '88888P8 '88888P' dP        !//
//!===========================================================!//
using ld = long double;
using ll = long long;
using ull = unsigned long long;
std::mt19937 mt{std::random_device{}()};
template <typename T>
constexpr T INF = std::numeric_limits<T>::max() / 4;
template <typename T>
constexpr T MOD = static_cast<T>(1000000007);
template <typename F>
constexpr F PI() { return 3.1415926535897932385; }
#define SHOW(...) (std::cerr << "(" << #__VA_ARGS__ << ") = ("), HogeHogeSansuu(__VA_ARGS__), std::cerr << ")" << std::endl;
struct has_debugPrint_impl
{
    template <class T>
    static auto check(T&& x) -> decltype(x.debugPrint(), std::true_type{});
    template <class T>
    static auto check(...) -> std::false_type;
};
template <class T>
class has_debugPrint : public decltype(has_debugPrint_impl::check<T>(std::declval<T>()))
{
};
template <bool>
struct HogeHogeDump
{
    template <typename T>
    static void dump(const T& x) { x.debugPrint(); }
};
template <>
struct HogeHogeDump<false>
{
    template <typename T>
    static void dump(const T& x) { std::cerr << x; }
};
void HogeHogeSansuu() { ; }
template <typename T>
void HogeHogeSansuu(const T& x) { HogeHogeDump<has_debugPrint<T>::value>::dump(x); }
template <typename T, typename... Args>
void HogeHogeSansuu(const T& x, Args... args) { HogeHogeDump<has_debugPrint<T>::value>::dump(x), std::cerr << ",", HogeHogeSansuu(args...); }
template <typename T>
bool chmin(T& a, const T& b) { return a = std::min(a, b), a == b; }
template <typename T>
bool chmax(T& a, const T& b) { return a = std::max(a, b), a == b; }
template <typename T, typename F>
void For(const T s, const T t, const F f)
{
    for (T i = s; i != t; i += T(s < t ? 1 : -1)) { f(i); }
}
template <typename T, typename F>
void Rep(const T N, const F f) { For<T, F>(0, N, f); }
template <typename T, typename F>
void RRep(const T N, const F f) { For<T, F>(N - 1, -1, f); }
template <typename T>
std::vector<T> Vec(const std::size_t n, T v) { return std::vector<T>(n, v); }
template <class... Args>
auto Vec(const std::size_t n, Args... args) { return std::vector<decltype(Vec(args...))>(n, Vec(args...)); }
template <typename T>
constexpr T PopCount(T v) { return v = (v & 0x5555555555555555ULL) + (v >> 1 & 0x5555555555555555ULL), v = (v & 0x3333333333333333ULL) + (v >> 2 & 0x3333333333333333ULL), v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL, static_cast<T>(v * 0x0101010101010101ULL >> 56 & 0x7f); }
template <typename T>
constexpr T log2p1(T v) { return v |= (v >> 1), v |= (v >> 2), v |= (v >> 4), v |= (v >> 8), v |= (v >> 16), v |= (v >> 32), PopCount(v); }
template <typename T>
constexpr bool ispow2(const T v) { return (v << 1) == (T(1) << (log2p1(v))); }
template <typename T>
constexpr T ceil2(const T v) { return ispow2(v) ? v : T(1) << log2p1(v); }
template <typename T>
constexpr T floor2(const T v) { return v == 0 ? T(0) : ispow2(v) ? v : T(1) << (log2p1(v) - 1); }
template <typename T>
struct Accum
{
    template <typename InIt>
    Accum(const InIt first, const InIt last) : accum(std::size_t(std::distance(first, last))) { std::partial_sum(first, last, accum.begin()); }
    T sum(const std::size_t i) const { return i == 0 ? T(0) : accum[i - 1]; }
    T sum(const std::size_t l, const std::size_t r) const { return sum(r) - sum(l); }
    std::vector<T> accum;
};
template <typename T>
struct Accum2D
{
    Accum2D(const std::vector<std::vector<T>>& t) : accum{t}
    {
        for (std::size_t i = 0; i < accum.size(); i++) {
            for (std::size_t j = 1; j < accum[i].size(); j++) { accum[i][j] += accum[i][j - 1]; }
        }
        for (std::size_t i = 1; i < accum.size(); i++) {
            for (std::size_t j = 0; j < accum[i].size(); j++) { accum[i][j] += accum[i - 1][j]; }
        }
    }
    T sum(const std::size_t y, const std::size_t x) const { return y == 0 or x == 0 ? T(0) : accum[y - 1][x - 1]; }
    T sum(const std::size_t ymin, const std::size_t ysup, const std::size_t xmin, const std::size_t xsup) const { return sum(ysup, xsup) - sum(ymin, xmin); }
    std::vector<std::vector<T>> accum;
};
template <typename T>
struct Zip
{
    template <typename InIt>
    Zip(const InIt first, const InIt last) : unzip(std::size_t(std::distance(first, last)))
    {
        std::copy(first, last, unzip), std::sort(unzip.begin(), unzip.end()), unzip.erase(std::unique(unzip.begin(), unzip.end()), unzip.end());
        for (std::size_t i = 0; i < unzip.size(); i++) { zip[unzip[i]] = i; }
    }
    std::vector<T> unzip;
    std::map<T, std::size_t> zip;
};
template <typename T, std::size_t N>
std::ostream& operator<<(std::ostream& os, const std::array<T, N>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
template <typename T, typename A>
std::ostream& operator<<(std::ostream& os, const std::deque<T, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
template <typename K, typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::multimap<K, T, C, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
    return (os << "]" << std::endl);
}
template <typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::multiset<T, C, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
template <typename K, typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::map<K, T, C, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
    return (os << "]" << std::endl);
}
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, const std::pair<T1, T2>& v) { return (os << "<" << v.first << "," << v.second << ">"); }
template <typename T1, typename T2, typename T3>
std::ostream& operator<<(std::ostream& os, const std::priority_queue<T1, T2, T3>& v)
{
    auto q = v;
    os << "[";
    while (not q.empty()) { os << q.top() << ",", q.pop(); }
    return os << "]\n";
}
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, const std::queue<T1>& v)
{
    auto q = v;
    os << "[";
    while (not q.empty()) { os << q.front() << ",", q.pop(); }
    return os << "]\n";
}
template <typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::set<T, C, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, const std::stack<T1>& v)
{
    auto q = v;
    os << "[";
    while (not q.empty()) { os << q.top() << ",", q.pop(); }
    return os << "]\n";
}
template <typename K, typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_multimap<K, T, H, P, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
    return (os << "]" << std::endl);
}
template <typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_multiset<T, H, P, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
template <typename K, typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_map<K, T, H, P, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
    return (os << "]" << std::endl);
}
template <typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_set<T, H, P, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
template <typename T, typename A>
std::ostream& operator<<(std::ostream& os, const std::vector<T, A>& v)
{
    os << "[";
    for (const auto& e : v) { os << e << ","; }
    return (os << "]" << std::endl);
}
//!====================================================================================================!//
//!   888888ba           oo                         88888888b                   dP                     !//
//!   88    '8b                                     88                          88                     !//
//!  a88aaaa8P' 88d888b. dP 88d8b.d8b. .d8888b.    a88aaaa  d8888b. .d8888b. d8888P .d8888b. 88d888b.  !//
//!   88        88'  '88 88 88''88''88 88ooood8     88     88'  '88 88'  '""   88   88'  '88 88'  '88  !//
//!   88        88       88 88  88  88 88.  ...     88     88.  .88 88.  ...   88   88.  .88 88        !//
//!   dP        dP       dP dP  dP  dP '88888P'     dP     '88888P8 '88888P'   dP   '88888P' dP        !//
//!====================================================================================================!//
template <typename T>
std::vector<std::pair<T, std::size_t>> PrimeFactors(T n)
{
    std::vector<std::pair<T, std::size_t>> ans;
    for (T i = 2; i * i <= n; i++) {
        std::size_t cnt = 0;
        for (; n % i == 0; n /= i, cnt++) {}
        if (cnt > 0) { ans.push_back({i, cnt}); }
    }
    if (n > 1) { ans.push_back({n, 1}); }
    return ans;
}
//!================================================================!//
//!  888888ba  oo          oo                                      !//
//!  88    '8b                                                     !//
//!  88     88 dP dP   .dP dP .d8888b. .d8888b. 88d888b. .d8888b.  !//
//!  88     88 88 88   d8' 88 Y8ooooo. 88'  '88 88'  '88 Y8ooooo.  !//
//!  88    .8P 88 88 .88'  88       88 88.  .88 88             88  !//
//!  8888888P  dP 8888P'   dP '88888P' '88888P' dP       '88888P'  !//
//!================================================================!//
template <typename T>
std::vector<T> Divisors(const T n)
{
    std::vector<T> head, tail;
    for (T i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            head.push_back(i);
            if (i * i != n) { tail.push_back(n / i); }
        }
    }
    for (auto it = tail.rbegin(); it != tail.rend(); it++) { head.push_back(*it); }
    return head;
}
//!===============================================================!//
//!   88888888b            dP       .88888.   a88888b. 888888ba   !//
//!   88                   88      d8'   '88 d8'   '88 88    '8b  !//
//!  a88aaaa    dP.  .dP d8888P    88        88        88     88  !//
//!   88         '8bd8'    88      88   YP88 88        88     88  !//
//!   88         .d88b.    88      Y8.   .88 Y8.   .88 88    .8P  !//
//!   88888888P dP'  'dP   dP       '88888'   Y88888P' 8888888P   !//
//!===============================================================!//
template <typename T>
constexpr std::pair<T, T> extgcd(const T a, const T b)
{
    if (b == 0) { return std::pair<T, T>{1, 0}; }
    const auto p = extgcd(b, a % b);
    return {p.second, p.first - p.second * (a / b)};
}
template <typename T>
constexpr T inverse(const T a, const T mod) { return (mod + extgcd((mod + a % mod) % mod, mod).first % mod) % mod; }
//!===============================================================!//
//!  888888ba  8888ba.88ba                 dP dP            dP    !//
//!  88    '8b 88  '8b  '8b                88 88            88    !//
//!  88     88 88   88   88 .d8888b. .d888b88 88 88d888b. d8888P  !//
//!  88     88 88   88   88 88'  '88 88'  '88 88 88'  '88   88    !//
//!  88    .8P 88   88   88 88.  .88 88.  .88 88 88    88   88    !//
//!  8888888P  dP   dP   dP '88888P' '88888P8 dP dP    dP   dP    !//
//!===============================================================!//
template <typename T>
class DModInt
{
private:
    T value;

public:
    const T mod;  // 正の数を渡すこと！(割り算を使う場合は素数)
    DModInt(const T val, const T mod) : value{((val % mod) + mod) % mod}, mod{mod} { assert(mod > 0); }
    DModInt(const DModInt<T>& n) : value{n()}, mod{n.mod} {}
    DModInt<T>& operator=(const DModInt<T>& n) { return assert(n.mod == mod), value = n(), (*this); }
    DModInt<T>& operator=(const T v) { return value = (mod + v % mod) % mod, (*this); }
    DModInt<T> operator+() const { return *this; }
    DModInt<T> operator-() const { return DModInt{mod - value, mod}; }
    DModInt<T> operator+(const DModInt<T>& val) const { return assert(mod == val.mod), DModInt{value + val(), mod}; }
    DModInt<T> operator-(const DModInt<T>& val) const { return assert(mod == val.mod), DModInt{value - val() + mod, mod}; }
    DModInt<T> operator*(const DModInt<T>& val) const { return assert(mod == val.mod), DModInt{value * val(), mod}; }
    DModInt<T> operator/(const DModInt<T>& val) const { return assert(mod == val.mod), DModInt{value * inverse(val(), mod), mod}; }
    DModInt<T>& operator+=(const DModInt<T>& val) { return assert(mod == val.mod), (((value += val()) %= mod) += mod) %= mod, (*this); }
    DModInt<T>& operator-=(const DModInt<T>& val) { return assert(mod == val.mod), (((value -= val()) %= mod) += mod) %= mod, (*this); }
    DModInt<T>& operator*=(const DModInt<T>& val) { return assert(mod == val.mod), (((value *= val()) %= mod) += mod) %= mod, (*this); }
    DModInt<T>& operator/=(const DModInt<T> val) { return assert(mod == val.mod), (((value *= inverse(val(), mod)) %= mod) += mod) %= mod, (*this); }
    DModInt<T> operator+(const T val) const { return DModInt{value + val, mod}; }
    DModInt<T> operator-(const T val) const { return DModInt{value - val, mod}; }
    DModInt<T> operator*(const T val) const { return DModInt{value * val, mod}; }
    DModInt<T> operator/(const T val) const { return DModInt{value * inverse(val, mod), mod}; }
    template <typename I>
    DModInt<T> operator^(const I n) const { return n < 0 ? (T(1) / (*this)) ^ (-n) : n == 0 ? DModInt{1, mod} : n % 2 == 1 ? (*this) * ((*this) ^ (n - 1)) : ((*this * *this) ^ (n / 2)); }
    DModInt<T>& operator+=(const T val) { return (((value += val) %= mod) += mod) %= mod, (*this); }
    DModInt<T>& operator-=(const T val) { return (((value -= val) %= mod) += mod) %= mod, (*this); }
    DModInt<T>& operator*=(const T val) { return (((value *= val) %= mod) += mod) %= mod, (*this); }
    DModInt<T>& operator/=(const T val) { return (((value *= inverse(val, mod)) %= mod) += mod) %= mod, (*this); }
    template <typename I>
    DModInt<T>& operator^=(const I n) { return (*this) = ((*this) ^ n); }
    bool operator==(const DModInt<T>& val) const { return assert(mod == val.mod), value == val.value; }
    bool operator!=(const DModInt<T>& val) const { return assert(mod == val.mod), not(*this == val); }
    bool operator==(const T val) const { return value == (mod + val % mod) % mod; }
    bool operator!=(const T val) const { return not(*this == val); }
    T operator()() const { return value; }
};
template <typename T>
inline DModInt<T> operator+(const T val, const DModInt<T>& n) { return DModInt<T>{n() + val, n.mod}; }
template <typename T>
inline DModInt<T> operator-(const T val, const DModInt<T>& n) { return DModInt<T>{-n() + val, n.mod}; }
template <typename T>
inline DModInt<T> operator*(const T val, const DModInt<T>& n) { return DModInt<T>{n() * val, n.mod}; }
template <typename T>
inline DModInt<T> operator/(const T val, const DModInt<T>& n) { return DModInt<T>{val, n.mod} / n; }
template <typename T>
inline bool operator==(const T val, const DModInt<T>& n) { return n == val; }
template <typename T>
inline bool operator!=(const T val, const DModInt<T>& n) { return not(val == n); }
template <typename T>
inline std::istream& operator>>(std::istream& is, DModInt<T>& n)
{
    T v;
    return is >> v, n = v, is;
}
template <typename T>
std::ostream& operator<<(std::ostream& os, const DModInt<T>& n) { return (os << n()); }
using dmint = DModInt<int>;
using dmll = DModInt<ll>;
//!====================================================================================!//
//!    .88888.   a88888b. 888888ba        d88b       dP         a88888b. 8888ba.88ba   !//
//!   d8'   '88 d8'   '88 88    '8b       8''8       88        d8'   '88 88  '8b  '8b  !//
//!   88        88        88     88       d8b        88        88        88   88   88  !//
//!   88   YP88 88        88     88     d8P'8b       88        88        88   88   88  !//
//!   Y8.   .88 Y8.   .88 88    .8P     d8' '8bP     88        Y8.   .88 88   88   88  !//
//!    '88888'   Y88888P' 8888888P      '888P''YP    88888888P  Y88888P' dP   dP   dP  !//
//!====================================================================================!//
template <typename T>
constexpr T gcd(const T a, const T b) { return (b != 0) ? gcd(b, a % b) : a; }
template <typename T>
constexpr T lcm(const T a, const T b) { return (a == 0 and b == 0) ? (T)0 : (a / gcd(a, b)) * b; }
int main()
{
    ll N;
    std::cin >> N;
    const auto facs = PrimeFactors(N);
    ll phi = 1;
    for (const auto& p : facs) {
        if (p.second > 1) { return std::cout << -1 << std::endl, 0; }
        phi = lcm(phi, p.first - 1);
    }
    if (gcd(phi, N) != 1) { return std::cout << -1 << std::endl, 0; }
    const auto facs2 = PrimeFactors(phi);
    ll phi2 = phi;
    for (const auto& p : facs2) { (phi2 *= (p.first - 1)) /= p.first; }
    const auto D = Divisors(phi2);
    const DModInt<ll> DN(N, phi);
    for (const auto d : D) {
        if ((DN ^ d) == 1) { return std::cout << d << std::endl, 0; }
    }
    std::cout << -1 << std::endl;
    return 0;
}



Measured memory_bytes: 3204