func_code_string: #include <bits/stdc++.h>   using namespace std;   const int mod = 1e9 + 7;   const int N = 1e6 + 4;   bool isPrime(int n) {     if (n <= 1) return false;     if (n <= 3) return true;     if (n % 2 == 0 || n % 3 == 0) return false;     for (int i = 5; i * i <= n; i = i + 6)       if (n % i == 0 || n % (i + 2) == 0) return false;     return true;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long test = 1;     cin >> test;     for (int qw = 1; qw <= test; qw++) {       int n;       cin >> n;       int a[n];       for (int i = 0; i < n; i++) cin >> a[i];       int sum = 0;       for (int i = 0; i < n; i++) sum += a[i];       if (!isPrime(sum)) {         cout << n << endl;         for (int i = 1; i <= n; i++) cout << i <<    ;         cout << endl;       } else {         int flag = 0;         for (int i = 0; i < n; i++) {           if (!isPrime(sum - a[i])) {             cout << n - 1 << endl;             flag = 1;             for (int j = 0; j < n; j++) {               if (i != j) cout << j + 1 <<    ;             }             cout << endl;           }           if (flag == 1) break;         }       }     }     return 0;   }   