A1071 | $[COCI-2006_2007-contest3]#1 BICIKLI$

来源COCI

时间限制1s

内存限制128MB

通过 / 提交0/0

题目描述

A bicycle race is being organized in a land far, far away. There are N town in the land, numbered 1 through N. There are also M one-way roads between the towns. The race will start in town 1 and end in town 2. How many different ways can the route be set? Two routes are considered different if they do not use the exact same roads.

The first line of input contains two integers N and M (1 \leq N \leq 10 000, 1 \leq M \leq 100 000), the number of towns and roads. Each of the next M lines contains two different integers A and B, representing a road between towns A and B. Towns may be connected by more than one road.

Output the number of distinct routes that can be set on a single line. If that number has more than nine digits, output only the last nine digits of the number. If there are infinitely many routes, output "inf".

输入 #1

输出 #1

输入 #2

输出 #2

inf

输入 #3

输出 #3

073741824

C++ 编辑器

输入

输出