func_code_string: #include <bits/stdc++.h>   using namespace std;   const int mod = 1e9 + 7;   const int MX = 1e5 + 6;   long long l, r;   int main() {     cin >> l >> r;     puts( YES );     for (long long i = l; i <= r; i += 2) cout << i <<     << i + 1 << endl;     return 0;   }   