func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long t, n;     string s;     cin >> t;     while (t--) {       cin >> n >> s;       long long ans = 0, o = 0, ans1 = 0;       for (long long i = 0; i < n; i++) {         if ((s[i] - 48) % 2 == 1) {           ans = (ans * 10) + (s[i] - 48);           ans1 += ans;           if (ans1 % 2 == 0) {             o = 1;             break;           }         }       }       if (o == 0)         cout << -1 <<   n ;       else         cout << ans <<   n ;     }     return 0;   }   