#include<iostream> using namespace std; int getsum(int a){ int he=0; int sum=0; for(int i=2;i<=a;i++){ he=0; for(int j=1;j<=i;j++){ if(i%j==0){ he++; } } if(he==2){ sum++; } } return sum; } int main() { int b; cin>>b; cout<<getsum(b); return 0; }