Sieve

#include <bits/stdc++.h>

using namespace std ;

vector <long long> Pr ;

bool isPrime[20000000] ;
void Sieve(long long n){
    isPrime[0] = 1 , isPrime[1] = 1 ;

    for(long long i = 2 ; i <= n ; i++){
        if(!isPrime[i]){
                Pr.push_back(i) ;
            for(long long j = i * i ; j <= n ; j += i)
                isPrime[j] = 1 ;
        }
    }
}

int main(){
    long long n = 20000000 ;
    Sieve(n) ;

        cout << "Mohammed is Here :D " << endl;

    return 0;
}