#include <bits/stdc++.h>   using namespace std;   int main() {     long long n, s = 1;     char a;     string b[10], c;     cin >> n;     b[0] =   ;     b[1] =   ;     b[2] =  2 ;     b[3] =  3 ;     b[4] =  322 ;     b[5] =  5 ;     b[6] =  53 ;     b[7] =  7 ;     b[8] =  7222 ;     b[9] =  7332 ;     int k = 0;     int d = 0;     for (int i = 1; i <= n; i++) {       cin >> a;       s = a - 48;       if (s != 1 && s != 0) c = c + b[s];     }     sort(c.begin(), c.end());     k = c.size();     for (int i = k - 1; i >= 0; i--) cout << c[i];     return 0;   }   