/home/stepan7/sandbox/main.php:40:
array(2) {
  [0] =>
  int(1)
  [1] =>
  int(37)
}
/home/stepan7/sandbox/main.php:15:
int(1)
PHP Fatal error:  Uncaught OutOfRangeException: Index out of range: 1, expected 0 <= x <= 0 in /home/stepan7/sandbox/main.php:17
Stack trace:
#0 /home/stepan7/sandbox/main.php(41): bfs()
#1 {main}
  thrown in /home/stepan7/sandbox/main.php on line 17