#include <iostream>
#include <vector>
using namespace std;
const int MAXN = 1e7+5;
vector<long long> prime;
bool isPrime[MAXN];
void init() {
for(int i = 0;i < MAXN;i++)
isPrime[i] = true;
for(long long i = 2;i < MAXN;i++) {
if(!isPrime[i]) continue;
...