#include <bits/stdc++.h>
using namespace std;
const int maxn = 1000020;
char arry[maxn];
char unbeutf[maxn];
bool def1 = false, def2 = false;
int main() {
  int n, peg = 0;
  long long flag;
  cin >> n;
  while (n--) {
    cin >> arry;
    if (strlen(arry) == 1 && arry[0] == '0')
      def1 = true;
    else {
      flag = 0;
      for (int i = 0; i < strlen(arry); ++i) {
        if (arry[i] == '0') ++flag;
      }
      if (strlen(arry) - flag != 1 || (strlen(arry) == 1 && arry[0] != '1') ||
          (strlen(arry) - flag == 1 && arry[0] != '1')) {
        strcpy(unbeutf, arry);
        flag = 0;
        def2 = true;
      }
      peg += flag;
    }
  }
  if (def1)
    cout << '0';
  else if (def2) {
    cout << unbeutf;
    while (peg--) cout << '0';
  } else {
    cout << '1';
    while (peg--) cout << '0';
  }
  return 0;
}
