OJ Board

hello everyone i really need some help here
i have done this problem by using floyd algorithm
i don't know if this is the correct approch or not.
when i give 2000 cities it take alot of time for the code to finish so it is very slow.
what is the best way to solve this question and why ...

thanks a million for you help greve

thanks alot for the website.
and thank for the hint about the first number after M.

but it i still getting WA
i think because in the question it says that 0<=M<=10^1000
WHEN I try to store 10^100 it gives me wrong numbers
if you can tell me how to avoid OVERFLOW in this condition

thanks alot in ...

i would really be thankful if you guys gave me some I/Os. because i have written this code but the problem is i keeping getting WA

thanks in advance