Need regex to match 1 or more of exactly n-digit numbers -

i need regex match series of 1 or more n-digit numbers, separated comma, ie:

abc12345def returns 12345
abc12345,23456def returns 12345,23456

so far got this: \d{5}(,\d{5})*

problem matches in cases these:

123456 returns 12345, need not match if number longer 5. need numbers of 5 digits, , if number shorter or longer it's no-match

thanks

which language using regexes? want put non-digit markers around \d{5}'s; here perl syntax (with negative look-ahead/look-behind fix lukasz):

(?<![\d,])\d{5}(,\d{5})*(?![\d,])