Quiz 30: Find number of keys which need to get repaired

Problem:

Given number of broken keyboard keys and a string. Find how many keys need to be repair to type this string

Input Format: 

Broken keys without any spaces
String to be typed

Output Format: 
Number of keys which need to be repaired

Constraints: 
none

Sample Input

aspzq
happiness

Sample Output:
3

Explanations:
keys a,s and p need to be repaired

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Solution:

chomp($n=<STDIN>);
@br=split("",$n);
$len=@br;
$count=0;
chomp($str=<STDIN>);
@arr=split("",$str);
$len1=@arr;
for($j=0;$j<$len;$j++)
{
if($str =~ /$br[$j]/)
{
$count++;
}
}
print "$count";

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Tips:

To type p two times, key which need to repaired is key p, so count will not be doubled.