// ki bood ke goft Ghatinga?

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<pii,int> ppiii;

// vectors and Sets:
#define vc vector
#define pb push_back
#define all(c) (c).begin(), (c).end()

// pairs
#define mp make_pair
#define fr first
#define sc second

// execution time check and Debug
#define StartEX clock_t startExeTime = clock();
#define EndEX clock_t endExeTime = clock();
#define ExTime cerr << "\nTotal Execution Time is: " << double(-double(startExeTime)+double(endExeTime)) / CLOCKS_PER_SEC;
#define debug(x) cerr << #x << " : " << x << '\n'
#define endl "\n"

// time optimization
#define Heh ios::sync_with_stdio(false);cin.tie(0);
#define Bah ios::sync_with_stdio(false);
#pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")

// useful functions
ll pw(ll a,ll b){
  ll ret = 1;
  ll mul = a;
  while(b > 0){
	if(b&1)
	  ret = (ret * mul);
	mul = (mul * mul);
	b >>= 1;
  }
  return ret;
}
ll pw(ll a,ll b,ll mod){
  ll ret = 1;
  ll mul = a;
  while(b > 0){
	if(b&1)
	  ret = (ret * mul) % mod;
	mul = (mul * mul) % mod;
	b >>= 1;
  }
  return ret;
}

ll to_int(string s){
  ll ret = 0;
  for(int i = 0 ; i < (int)s.size() ; i++) ret = 10 * ret + s[i] - '0';
  return ret;
}

bool deq(ld a , ld b){return (abs(a-b) < 0.000001);} // 10 ^ -6

const int MAXP = 1e6 + 16;

int main()
{
  int p[MAXP] = {};
  vc<int> pr;
  for(int i = 2 ; i < MAXP ; i++){
    if(p[i] == 0){
      pr.pb(i);
      for(int j = i ; j < MAXP ; j += i) p[j] = i;
    }
  }

  int f[MAXP];
  f[1] = 1;
  for(int i = 2 ; i < MAXP ; i++){
    int x = i;
    int pi = p[i] , pp = 1;
    while(x % pi == 0) x /= pi , pp++;
    f[i] = f[x] * pp;
  }

  ll x;
  cin >> x;
  ll y = x;
  for(int i = 2 ; i < MAXP ; i++){
    while(y % i == 0) y /= i;
  }
  for(int i = 1 ; i < MAXP ; i++){
    ll nf = 1;
    for(int _ = 0 ; _ < f[i] ; _++){
      if((__int128)nf * i > (__int128)x){
	nf = 0;
	break;
      }
      nf *= i;
    }
    if(nf == x){
      cout << i << endl;
      return 0;
    }
  }
  ll px = sqrt(x);
  for(ll i = max(0ll , px-2) ; i <= px+2 ; i++){
    if(i * i == x){
      px = i;
      break;
    }
  }
  if(px * px == x and y == x) cout << px << endl;
  else cout << -1 << endl;
}

// ki seda kard Patinga?