#!/usr/bin/perl
# your code goes here
$txt = "1,2,3,{4,5,6,7,8},9,10,100";
$txt =~ s/(\{\s*|(?<!^)\G)(\d+),(?=[,0-9]*\})/$1$2|/g;
IyEvdXNyL2Jpbi9wZXJsCiMgeW91ciBjb2RlIGdvZXMgaGVyZQoKJHR4dCA9ICIxLDIsMyx7NCw1LDYsNyw4fSw5LDEwLDEwMCI7CiR0eHQgPX4gcy8oXHtccyp8KD88IV4pXEcpKFxkKyksKD89WywwLTldKlx9KS8kMSQyfC9nOwpwcmludCAkdHh0Ow==