($a,$b,$c)=sort{$a-$b}glob<>;

$x+=$a;
$b-=$a;
$c-=$a;
$a-=$a;

$t=$b<$c/3?$b:$c/3|0;
$x+=$t;
$b-=$t;
$c-=$t*3;

$t=$c<$b/3?$c:$b/3|0;
$x+=$t;
$c-=$t;
$b-=$t*3;

$x+=$c/5|0;
$c%=5;

print$x