$turn = fgets(STDIN);
$hairetsu = [];


$all_ans = [0,1,2,3,4,5,6,7,8,9]; 
$all_del = [];

for ($i=0; $i<$turn; $i++) {
    
    $hairetsu[] = explode(" ", trim(fgets(STDIN)));
    
    $result = array_slice($hairetsu[$i] , 4, 1);
    
    if($result[0] == "NO"){
        $add_del = array_slice($hairetsu[$i] , 0, 4);
        $all_del = array_merge($all_del, $add_del);
    }
    
}

$unique = array_unique($all_del);

foreach($unique as $u){
    //削除実行
    if(($key = array_search($u, $all_ans)) !== false) {
        unset($all_ans[$key]);
    } 
}
$val = array_values($all_ans);
echo $val[0]."\n";