C++ 

giúp với ạ hứa vote 5 sao

#include <bits/stdc++.h>

using namespace std;

bool check (long long x)
{
  for (long long i = 2; i <= sqrt(x); ++i)
  if (x % i == 0) return false;
  return x > 1;
}
long long a[1005], n, d = 0;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (long long i = 1; i <= n; ++i) cin >> a[i];
  for (long long i = 1; i <= n; ++i)
  {
    for (long long j = i + 1; j <= n; ++j)
    {
      if (check(a[i] + a[j])) d++;
    }
  }
  cout << d;
  return 0;
}

#include <iostream>
#include <math.h>
using namespace std;
bool ok(int n) {
    for (int i=2; i<=sqrt(n); i++) if (n%i==0) return false;
    return n>=2;
}
int main() {
    int n;
    cin >> n;
    int a[n];
    for (int i=0; i<n; i++) cin >> a[i];
    int count=0;
    for (int i=0; i<n-1; i++) for (int j=i+1; j<n; j++) if (ok(a[i]+a[j])) 
    count++;
    cout<<count;
}