<?php
 
function migratoryBirds($n, $ar) { 
    $passaros = [];
    foreach ($ar as $passaro){
        $passaros[$passaro] = ($passaros[$passaro] ?? 0) + 1;
    }
 
    $maiorContagem = 0;
    $menorId = $ar[0];
    foreach ($passaros as $id => $contagem) {
        if ($contagem > $maiorContagem || ($contagem == $maiorContagem && $id < $menorId)){
            $maiorContagem = $contagem;
            $menorId = $id;
        }
    }
 
    return $menorId;
}
 
$arr = [5,5,5,3,3,3];
var_dump(migratoryBirds(count($arr),$arr));
$arr =  [3,4,2,5,4];
var_dump(migratoryBirds(count($arr),$arr));
 

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