#include #include #include #include typedef long long ll; using namespace std; vector sieve_of_eratosthenes(int n) { // enumerate primes in [2,n] with O(n log log n) vector is_prime(n+1, true); is_prime[0] = is_prime[1] = false; for (int i = 2; i*i <= n; ++i) if (is_prime[i]) for (int k = i+i; k <= n; k += i) is_prime[k] = false; vector primes; for (int i = 2; i <= n; ++i) if (is_prime[i]) primes.push_back(i); return primes; } vector factors(ll n, vector const & primes) { vector result; for (int p : primes) { if (n < p *(ll) p) break; while (n % p == 0) { result.push_back(p); n /= p; } } if (n != 1) result.push_back(n); return result; } int main() { ll n; scanf("%lld", &n); auto primes = sieve_of_eratosthenes(sqrt(n)); vector ps = factors(n, primes); set qs; for (ll p : ps) { if (qs.count(p)) { qs.erase(p); } else { qs.insert(p); } } ll r = 1; for (ll q : qs) r *= q; printf("%lld\n", r); return 0; }