#include <bits/stdc++.h>
char s[100009];
char num[100009];
int main() {
  int n, i, j, cnt, cnt2 = 0, len, flag = 1;
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%s", s);
    len = strlen(s);
    cnt = 0;
    if (len == 1 && s[0] == '0') {
      printf("0");
      return 0;
    }
    for (j = 0; j < len; j++) {
      if (s[j] == '1')
        cnt++;
      else if (s[j] != '0')
        cnt = 999;
    }
    if (cnt > 1) {
      for (j = 0; j < len; j++) num[j] = s[j];
      flag = 0;
    } else
      cnt2 += len - cnt;
  }
  if (flag)
    printf("1");
  else
    printf("%s", num);
  for (i = 0; i < cnt2; i++) printf("0");
  return 0;
}
