use strict;
use warnings;

my $s = <>;
chomp $s;
my @count;


for(my $i = 0; $i < 3; $i++) {
	$count[$i] = 0;
}

$count[0] = (() = $s =~ /t/g);
$count[1] = (() = $s =~ /r/g);
$count[2] = (() = $s =~ /e/g);
$count[2] /= 2;
$count[2] = int $count[2];

@count = sort {$a <=> $b} @count;

print "$count[0]\n";

exit;