func_code_string: #include <bits/stdc++.h>   using namespace std;   int32_t main() {     long long int a, b;     cin >> a >> b;     if (a == 9 and b == 1) {       cout << 9 <<     << 10;     } else if (a == b) {       cout << a * 10 <<     << a * 10 + 1;     } else if (b - a == 1) {       cout << a * 10 + 9 <<     << b * 10 << endl;     } else {       cout << -1 << endl;     }     return 0;   }   