#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:1024000000,1024000000")
char s[200010], ans[200010];
int main() {
  int n;
  scanf("%d", &n);
  bool zero = 0, flag = 0;
  int cnt = 0, cur = 0;
  for (int i = 0; i < n; ++i) {
    scanf("%s", s);
    if (s[0] == '0') zero = 1;
    int len = strlen(s), c0 = 0, c1 = 0, c2 = 0;
    for (int j = 0; j < len; ++j) {
      if (s[j] == '0')
        c0++;
      else if (s[j] == '1')
        c1++;
      else
        c2++;
    }
    if (c1 == 1 && c1 + c0 == len)
      cnt += c0;
    else {
      flag = 1;
      for (int j = 0; j < len; ++j) ans[cur++] = s[j];
    }
  }
  if (zero) {
    puts("0");
    return 0;
  }
  if (!flag) ans[cur++] = '1';
  for (int i = 0; i < cnt; ++i) ans[cur++] = '0';
  ans[cur] = '\0';
  printf("%s\n", ans);
  return 0;
}
