use strict;
use warnings;
use bigint;

my ($x, $y, $z) = split/ /, <>;
chomp $z;

my ($l, $r) = (0, 1000000000000000000);
while ($l + 1 < $r) {
  my $m = ($l + $r) / 2;
  my $ca = $m / $x;
  my $rz = $ca * $y + ($m - $ca);
  if ($z <= $rz) {
    $r = $m;
  } else {
    $l = $m;
  }
}

print "$r\n";