<?php
$week1 = trim(fgets(STDIN));
$week2 = trim(fgets(STDIN));
$day = array();
for($i = 0; $i < 7; $i++) {
  if($week1[$i] == 'o') {
    $day[$i] = 1;
  } else {
    $day[$i] = 0;
  }
}
for($i = 0; $i < 7; $i++) {
  if($week2[$i] == 'o') {
    $day[$i + 7] = 1;
  } else {
    $day[$i + 7] = 0;
  }
}
$holiday = array();
for($i = 0; $i < 14; $i++) {
  if($day[$i] == 1) {
    if($i > 0) {
      $holiday[$i] = $holiday[$i - 1] + 1;
    } else {
      $holiday[$i] = 1;
    }
  } else {
    $holiday[$i] = 0;
  }
}
$ans = 0;
for($i = 0; $i < 14; $i++) {
  $ans = max($ans, $holiday[$i]);
}
print($ans);
?>