**Location: The Quad**

The information about the Frosty Keypad acn be found by talking to Tangle Coalbox. This is summarized as:

Hint

I've got a few clues for you.

- One digit is repeated once.
- The code is a prime number.
- You can probably tell by looking at the keypad which buttons are used.

So looking at the picture of the keypad we can see that 1, 3 and 7 are the most smudged from use. This implies 3 number, but one is repeated once, so the code is 4 digits long and a prime number.

I found a list of prime numbers up to 10,000 and put them into a small perl program:

```
#!/usr/bin/perl
use strict;
use English;
my $primes="2, [SNIPPED FOR CLARITY], 9973";
foreach my $prime ( split(", ", $primes)){
my @digits = split("", $prime);
if( $#digits == 3) {
my $count_1 = 0;
my $count_3 = 0;
my $count_7 = 0;
my $count_other = 0;
foreach my $digit (@digits) {
if( $digit == 1 ) {
++$count_1;
} elsif ( $digit == 3 ) {
++$count_3;
} elsif ( $digit == 7 ) {
++$count_7;
} else {
++$count_other;
}
}
next if( $count_other > 0 );
next if( $count_1 > 2 || $count_3 > 2 ||$count_7 > 2 );
next if( $count_1 == 0 || $count_3 == 0 ||$count_7 == 0 );
print "$prime\n";
}
}
```

The result was the following list:

1373

1733

3137

3371

7331

The answer was 7331.