<?php
$a=fgets(STDIN);
$b=fgets(STDIN);
function roman_to_number($value)
{
$aRom=array("I"=>1,"V"=>5,"X"=>10); 
$aArb=str_split($value); 
$r=0; 
 for($x=0;$x<count($aArb);$x++) 
{ 
    if($aRom[$aArb[$x]]<$aRom[$aArb[$x+1]]){ 
        $r+=$aRom[$aArb[$x+1]]-$aRom[$aArb[$x]]; 
        $x++; 
    } 
    else{ 
        $r+=$aRom[$aArb[$x]]; 
    } 
} 
return $r;
}
$n1= roman_to_number($a);
$n2= roman_to_number($b);
$s=$n1+$n2;
function number_to_roman($value)
{
	$table=array(10=>"X", 9=>"IX", 5=>"V",4=>"IV",1=>"I");
	 while($value) {
        foreach($table as $part=>$fragment) if($part<=$value) break;
        $amount=(int)($value/$part);
        $value-=$part*$amount;
        $result.=str_repeat($fragment,$amount);
    }
    return $result;
}
$sum=number_to_roman($s);
echo $sum;
?>