#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef long double ld;
string to_string(string s) {
return '"' + s + '"';
}
string to_string(const char* s) {
return to_string((string) s);
}
string to_string(bool b) {
return (b ? "true" : "false");
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A>
string to_string(A v) {
bool first = true;
string res = "{";
for (const auto &x : v) {
if (!first) {
res += ", ";
}
first = false;
res += to_string(x);
}
res += "}";
return res;
}
void debug_out() {
cerr << endl;
}
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
cerr << " " << to_string(H);
debug_out(T...);
}
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
ll euclid(ll a, ll b, ll &x, ll &y) {
if (!b) return x = 1, y = 0, a;
ll d = euclid(b, a % b, y, x);
return y -= a/b * x, d;
}
ll mod; // change to something else
struct Mod {
ll x;
Mod(ll xx) : x(xx) {}
Mod operator+(Mod b) { return Mod((x + b.x) % mod); }
Mod operator-(Mod b) { return Mod((x - b.x + mod) % mod); }
Mod operator*(Mod b) { return Mod((x * b.x) % mod); }
Mod operator/(Mod b) { return *this * invert(b); }
Mod invert(Mod a) {
ll x, y, g = euclid(a.x, mod, x, y);
// assert(g == 1);
if (g != 1) throw 0;
return Mod((x + mod) % mod);
}
Mod operator^(ll e) {
if (!e) return Mod(1);
Mod r = *this ^ (e / 2); r = r * r;
return e&1 ? *this * r : r;
}
};
signed main() {
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit); // RTE if input wrong datatype
int a;
cin >> a >> mod;
try {
Mod ans = Mod(1) / Mod(a);
cout << ans.x;
} catch (...) {
cout << -1;
}
}