#include <bits/stdc++.h>   using namespace std;   const long long maxsize = 100000 + 9;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int T;     T = 1;     while (T--) {       long long i, j, k, m, n, flag = 0;       vector<int> v;       string s;       cin >> n >> s;       for (i = 0; i < n; i++) {         if (s[i] ==  2 ) {           v.push_back(2);         }         if (s[i] ==  3 ) {           v.push_back(3);         }         if (s[i] ==  4 ) {           v.push_back(3);           v.push_back(2);           v.push_back(2);         }         if (s[i] ==  5 ) {           v.push_back(5);         }         if (s[i] ==  6 ) {           v.push_back(5);           v.push_back(3);         }         if (s[i] ==  7 ) {           v.push_back(7);         }         if (s[i] ==  8 ) {           v.push_back(7);           v.push_back(2);           v.push_back(2);           v.push_back(2);         }         if (s[i] ==  9 ) {           v.push_back(7);           v.push_back(3);           v.push_back(3);           v.push_back(2);         }       }       sort(v.begin(), v.end());       for (i = v.size() - 1; i >= 0; i--) {         cout << v[i];       }       cout <<   n ;     }   }   