#include <bits/stdc++.h>
using namespace std;
char str[100005];
char strA[100005];
int main(int argc, char const* argv[]) {
  int n;
  scanf("%d", &n);
  int total = 0;
  bool iszero = false;
  bool print = false;
  for (int i = 0; i < n; i += 1) {
    scanf("%s", str);
    int len = strlen(str);
    int c1 = 0;
    int c0 = 0;
    int cX = 0;
    for (int j = 0; j < len; j += 1) {
      if (str[j] == '0')
        ++c0;
      else if (str[j] == '1')
        ++c1;
      else
        ++cX;
    }
    if (c1 > 1 || cX || (i == n - 1 && !print)) {
      print = true;
      strcpy(strA, str);
    } else
      total += c0;
    if (len == 1 && c0) iszero = true;
  }
  if (iszero)
    printf("0\n");
  else {
    printf("%s", strA);
    for (int i = 0; i < total; i += 1) {
      printf("0");
    }
    printf("\n");
  }
  return 0;
}
