func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long t, a, b;     cin >> t;     while (t--) {       cin >> a >> b;       int f = 0;       long long area = a * a - b * b;       if ((a - b) != 1)         cout <<  NO ;       else {         area = a + b;         for (int i = 2; i <= sqrt(a + b); i++) {           if (area % i == 0) {             cout <<  NO ;             f = 1;             break;           }         }         if (f == 0) cout <<  YES ;       }       cout << endl;     }   }   