#include<fstream.h>
#include<math.h>
#include<time.h>
#include<stdio.h>
long N,c,x,d,j;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int main()
{
 //long start,end;
//start = clock();
//delay(2000);


fin>>N;
c=0;
for(x=2;x*x<=N;x++)
{
d=0;
for(j=2;j<=sqrt(x);j++)
if(x%j==0)
d=1;
if(d==0)
c=c+1;
}
fout<<c*c;
//end = clock();
//printf("The time was: %f\n", (end - start) / CLK_TCK);
return 0;
}