#include<algorithm>

 #include<cstdio>

 #include<cmath>

 #include<cstring>

 #include<iostream>

 #define N 200000

 #define ll long long

 int mul[N+],mark[N+],p[N+];

 ll K;

 void init(){

     mul[]=;

     for (int i=;i<=N;i++){

         if (!mark[i]){

             p[++p[]]=i;

             mul[i]=;

         }

         for (int j=;j<=p[]&&p[j]*i<=N;j++){

             mark[i*p[j]]=;

             if (i%p[j]) mul[i*p[j]]=-mul[i];

             else{

                 mul[i*p[j]]=;

                 break;

             }

         }

     }

 }

 ll cal(ll x){

     ll sum=,t=sqrt(x);

     for (ll i=;i<=t;i++){

         sum+=x/(i*i)*mul[i];

     }

     return sum;

 }

 int main(){

     scanf("%lld",&K);

     init();

     ll l=K,r=25505460948LL,ans=;

     while (l<=r){

         ll mid=(l+r)>>;

         if (cal(mid)>=K) ans=mid,r=mid-;

         else l=mid+;

     }

     printf("%lld\n",ans);

 }