seive

#include<bits/stdc++.h>
using namespace std;

#define MAX 1003

bool pr[MAX];
vector<int>prime;

void seive()
{
    memset(pr,true,sizeof(pr));
    pr[1]=pr[0]=false;
    for(int i=2;i<MAX;i++){
        if(!pr[i])
            continue;
        prime.push_back(i);
        for(int j=i*2;j<MAX;j+=i)
            pr[j]=false;
    }

}

int main()
{
    int i,j;
    seive();
    cout<<prime.size()<<endl;
}