#include <bits/stdc++.h>   using namespace std;   int main() {   #ifdef DEBUG     freopen( a.in ,  r , stdin);   #endif     ios_base::sync_with_stdio(false), cin.tie(0);     int T;     cin >> T;     while (T--) {       int a[2];       cin >> a[0] >> a[1];       string s;       cin >> s;       int n = a[0] + a[1];       vector<pair<int, int>> x;       for (int i = 0; i < n / 2; ++i) {         if (s[i] ==  ?  && s[n - 1 - i] ==  ? ) {           x.emplace_back(i, n - 1 - i);         } else if (s[i] ==  ? ) {           a[s[n - 1 - i] -  0 ] -= 2;           s[i] = s[n - 1 - i];         } else if (s[n - 1 - i] ==  ? ) {           a[s[i] -  0 ] -= 2;           s[n - 1 - i] = s[i];         } else {           if (s[i] != s[n - 1 - i]) {             a[0] = -1;           } else {             a[s[i] -  0 ] -= 2;           }         }       }       if (a[0] < 0 || a[1] < 0) {         cout << -1 <<   n ;         continue;       }       for (int i = 0; i < x.size(); ++i) {         if (a[0] >= 2) {           s[x[i].first] = s[x[i].second] =  0 ;           a[0] -= 2;         } else if (a[1] >= 2) {           s[x[i].first] = s[x[i].second] =  1 ;           a[1] -= 2;         } else {           a[0] = -1;         }       }       if (a[0] < 0 || a[1] < 0) {         cout << -1 <<   n ;         continue;       }       if ((n & 1) && s[n / 2] !=  ? ) a[s[n / 2] -  0 ]--;       if ((n & 1) && s[n / 2] ==  ? ) s[n / 2] = a[0] ?  0  :  1 ;       if (a[0] < 0 || a[1] < 0)         cout << -1 <<   n ;       else         cout << s <<   n ;     }     return 0;   }