#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 7;
char tmp[maxn];
char ans[maxn];
int lenth;
bool zero, bea;
bool judge() {
  int len = strlen(tmp);
  bool flag = false, bea = false;
  ;
  if (len == 1 && tmp[0] == '0') zero = true;
  for (int i = 0; i < len; i++) {
    if (tmp[i] == '1' || tmp[i] == '0') {
      if (tmp[i] == '1') {
        if (!flag) {
          flag = true;
        } else {
          bea = true;
          break;
        }
      }
    } else {
      bea = true;
      break;
    }
  }
  if (bea) {
    strcpy(ans, tmp);
    return true;
  } else {
    if (flag) lenth += len - 1;
  }
  return false;
}
int main() {
  int n;
  while (scanf("%d", &n) != EOF) {
    lenth = 0;
    zero = false;
    bool one = false;
    for (int i = 0; i < n; i++) {
      scanf("%s", tmp);
      if (judge()) one = true;
    }
    if (!zero) {
      if (one)
        printf("%s", ans);
      else
        printf("1");
      for (int i = 0; i < lenth; i++) printf("0");
      printf("\n");
    } else
      printf("0\n");
  }
  return 0;
}
