1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<iostream>
 5 #include<algorithm>
 6 using namespace std;
 7 #define Maxm 1000010
 8 #define LL long long
 9 
10 LL pri[Maxm],pl,mu[Maxm];
11 bool vis[Maxm];
12 void init()
13 {
14     for(LL i=2;i<=Maxm-10;i++)
15     {
16         if(!vis[i]) pri[++pl]=i,mu[i]=-1;
17         for(LL j=1;j<=pl;j++)
18         {
19             if(pri[j]*i>Maxm-10) break;
20             vis[pri[j]*i]=1;
21             if(i%pri[j]==0) mu[pri[j]*i]=0;
22             else mu[i*pri[j]]=-mu[i];
23             if(i%pri[j]==0) break;
24         }
25     }
26 }
27 
28 LL n;
29 bool check(LL x)
30 {
31     LL ans=0;
32     for(LL i=2;i*i<=x;i++)
33     {
34         ans+=x/(i*i)*(-mu[i]);
35     }
36     return ans>=n;
37 }
38 
39 int main()
40 {
41     init();
42     scanf("%lld",&n);
43     LL l=0,r=30000000000LL;
44     while(l<r)
45     {
46         LL mid=(l+r)>>1;
47         if(check(mid)) r=mid;
48         else l=mid+1;
49     }
50     printf("%lld\n",l);
51     return 0;
52 }