<?php
$userLogin = [];
$count = 0;
while(true) {
    $input = trim(fgets(STDIN));
    if ($input == "login") {
        break;
    }
    $line = explode(' -> ', $input);
    $userLogin[$line[0]] = $line[1];
}
while(true) {
    $input = trim(fgets(STDIN ));
    if ($input == "end"){
            break;
    }
    $line = explode(' -> ', $input);
    if (!key_exists || !value_exists) {
        echo "$key: login failed" . PHP_EOL;
            $count++;
    } else {
                echo "$key: logged in successfully" . PHP_EOL;
    }
}
echo "unsuccessful login attempts: $count";