Here is a different way using progressive matching and the \G assertion to continue matching from that point. TIMTOWTDI

tachyon

my $nth = 3;
my $rep = 1;
my $chr = 'e';
my $str = "Terence and Philip are sweet";
$str =~ m/$chr/gc for (1..$nth); # eat up first $nth "$chr"s
$str =~ s/\G(.*?)$chr/$1$rep/g;  # replace the rest
print $str;
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