<?php

const STR = 'tree';

$stdin = trim(fgets(STDIN));
$arrStr = array_count_values(str_split(STR));
$arrResult = array();

foreach ($arrStr as $key => $val) {
	if ($val === 0) {
		continue;
	}
	$arrResult[] = floor(substr_count($stdin, $key)/$val);	
}

print(min($arrResult).PHP_EOL);