#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
const int INF = 0x3f3f3f3f;
char str[N], str2[N];
bool dead;
int _count(void) {
  int c = 0, d = 0;
  for (int i = 0; str[i]; ++i) {
    if (str[i] == '1') {
      if (c >= 1)
        return -1;
      else
        c++;
    } else if (str[i] == '0')
      d++;
    else
      return -2;
  }
  if (c == 0 && d == 1) dead = true;
  return d;
}
int main(void) {
  int n;
  scanf("%d", &n);
  int cnt = 0;
  bool flag = false;
  dead = false;
  getchar();
  for (int i = 0; i < n; ++i) {
    scanf("%s", &str);
    int len = strlen(str);
    int tmp = _count();
    if (tmp == -2 || tmp == -1) {
      flag = true;
      for (int j = 0; j < len; ++j) str2[j] = str[j];
      str2[len] = '\0';
    } else
      cnt += tmp;
  }
  if (dead)
    puts("0");
  else {
    if (flag) {
      printf("%s", str2);
    } else
      printf("1");
    for (int i = 0; i < cnt; ++i) printf("0");
    puts("");
  }
  return 0;
}
