Pirates' Path

Captain Jack Sparrow is once again stranded on the natives' island, where the natives again believe he is a God. But Jack is not one to give in easily (especially when his life is at stake), and he is trying to escape.

The island is split into separate areas by its many rivers. Two areas are adjacent only if a bridge connects them. Jack must travel from the area where he is held captive to the area where his beloved ship, the Black Pearl, is docked.

Keen to keep their "God" on the island, the natives post a guard on some of the bridges — exactly one man on each guarded bridge. Jack, ever unwilling to spend more effort than necessary (and wishing to be merciful to his devotees), wants to incapacitate as few guards as possible on his way to the Black Pearl. Report that smallest possible number of guards.

The first line contains four integers separated by single spaces:

n b s e

where $n$ is the number of areas, $b$ is the number of bridges, $s$ ($0 \le s \lt n$) is the area where Jack is held captive, and $e$ ($0 \le e \lt n$) is the area where the Black Pearl is located.

Each of the next $b$ lines describes one bridge with three integers separated by single spaces:

a b c

where $a$ and $b$ ($0 \le a, b \lt n$) are the two areas the bridge connects, and $c$ is either $0$ or $1$, indicating whether the bridge is guarded ($1$) or not ($0$). Each guarded bridge has exactly one guard.

There may be no path from Jack's area to the Black Pearl's area. In that case, print exactly one line:

It's over with Captain Jack. At least till Pirates of the Caribbean 3.

Otherwise, print exactly one line:

x native(s) on the easiest way for Captain Jack.

where x is the least number of guards on any path from the starting area to the area of the Black Pearl.