#include <bits/stdc++.h>
using namespace std;
int n, len;
int nr;
int nr1, nr0, nrc, ok = 0;
char a[100005], aux[100005];
int check() {
  nr1 = nr0 = nrc = 0;
  for (int i = 1; i <= len; i++)
    if (a[i] == '0')
      nr0++;
    else if (a[i] == '1')
      nr1++;
    else
      nrc++;
  if (nrc) return 1;
  if (nr1 > 1) return 1;
  return 0;
}
int main() {
  scanf("%d\n", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%s ", a + 1);
    len = strlen(a + 1);
    if (len == 1 && a[1] == '0') {
      printf("0");
      return 0;
    }
    if (check())
      memcpy(aux, a, sizeof(a)), ok = 1;
    else
      nr += nr0;
  }
  if (ok)
    printf("%s", aux + 1);
  else
    printf("1");
  for (int i = 1; i <= nr; i++) printf("0");
  return 0;
}
