sieve of eratosthenes

#include <bits/stdc++.h>

using namespace std;

struct pii{
  int64_t a, b;
};

vector <pii> factorise(int64_t n){
  vector<pii>
  for (int64_t i = 2; i * i <= n; i++){
    if (n % i > 0){
      continue;
    }
    res.push_back({i, 0});
    while (n % i == 0){
      ++res.back().b;
      n /= i;
    }
  }
  if (n > 1){
    res.push_back({n, 1});
  }
  return res;
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);

  int64_t n;
  cin >> n;
  vector<pii> divs = factorise(n);
  for (pii )
}