#include <bits/stdc++.h>   using namespace std;   int main() {     int com[] = {1, 4, 6, 8, 9};     long long int t;     cin >> t;     while (t--) {       int64_t k;       cin >> k;       string n;       cin >> n;       map<int, int> m;       for (int i = 0; i < n.size(); i++) {         m[n[i] -  0 ]++;       }       int flag = 1;       for (auto it : m) {         if (it.first == 1 || it.first == 4 || it.first == 6 || it.first == 8 ||             it.first == 9) {           flag = 0;           cout << 1 << endl << it.first << endl;           break;         }       }       if (flag) {         for (auto it : m) {           if (it.second > 1) {             cout << 2 << endl << it.first << it.first << endl;             flag = 0;             break;           }         }         if (n ==  32  || n ==  35 ) {           flag = 0;           cout << 2 << endl << n << endl;         }       }       if (flag) {         stack<int> s;         string temp =   ;         for (int i = 0; i < n.size(); i++) {           if (n[i] !=  3 ) {             temp += n[i];           }           if (temp.size() == 2) {             break;           }         }         cout << 2 << endl << temp << endl;       }     }   }   