1 #include <iostream>
2 #include <algorithm>
3 using namespace std;
4
5 const int maxn = 1e5 + 5;
6 int a[maxn];
7
8 int main(){
9 int t;
10 cin >> t;
11 while(t--){
12 int n;
13 cin >> n;
14 string s;
15 cin >> s;
16 int sum = 0;
17 bool l = true;
18 int i;
19 for(i = n-1;i >= 1;i -= 2){
20 sum += 2*i+1;
21 if(l){
22 if(s[i] == '0'){
23 a[i] = 2;
24 }
25 else
26 a[i] = 4;
27 if(s[i-1] == '0'){
28 a[i-1] = 1;
29 }
30 else a[i-1] = 3;
31 l = false;
32 }
33 else{
34 if(s[i] == '0'){
35 a[i] = 1;
36 }
37 else
38 a[i] = 3;
39 if(s[i-1] == '0'){
40 a[i-1] = 2;
41 }
42 else a[i-1] = 4;
43 l = true;
44 }
45 }
46 if(i == 0){
47 sum += 1;
48 if(l){
49 if(s[0] == '0'){
50 a[0] = 2;
51 }
52 else
53 a[0] = 4;
54 }
55 else{
56 if(s[0] == '0'){
57 a[0] = 1;
58 }
59 else
60 a[0] = 3;
61 }
62 }
63
64 if(sum%2){
65 cout << -1 << endl;
66 continue;
67 }
68 else{
69 for(int j = 0;j < n;j++){
70 cout << a[j] ;
71 }
72 cout << endl;
73 }
74
75 }
76 return 0;
77 }
