#!/usr/bin/env python3
from pyswip import Prolog

swipl = Prolog()
swipl.consult("trains.pl")

STATIONS = [ans["S"] for ans in swipl.query("station(S)")]

def route_length(From, To):
    return next(swipl.query(f"route_length({From}, {To}, L)"))["L"]

def main():
    for station in STATIONS:
        print(station)

    print(route_length(STATIONS[0], STATIONS[1]))

if __name__ == "__main__":
    main()