#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;using LL=__int128;
const int N=(1<<20)+5,M=100+5,K=600+5,mod=1e9+7,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(time(0));
ll n;
ll calc(int x){
	ll ans=1;
	for(int i=1;i*i<=x;i++) if(x%i==0){
		ans*=x;
		if(i*i!=x) ans*=x;
	}
	return ans;
}
void Solve(){
	scanf("%lld",&n);
	int p=sqrtl(n);
	if(1ll*p*p!=n){puts("-1");return;}
	for(int i=1;i<=100;i++)if(calc(i)==n) {printf("%d\n",i);return;}
	for(int i=10;i>1;i--) if(calc(powl(n,1.0/i)+eps)==n){printf("%d\n",(int)(powl(n,1.0/i)+eps));return;}
	puts("-1");
}
int main(){
	int t;
	// scanf("%d",&t);
	t=1;
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}