Codeforces Beta Round 80 (Div. 2 Only)
C
Cthulhu
Codeforces
未评级
原题
← BD →
翻译中…

...Once upon a time a man came to the sea. The sea was stormy and dark. The man started to call for the little mermaid to appear but alas, he only woke up Cthulhu...

翻译中…

Whereas on the other end of the world Pentagon is actively collecting information trying to predict the monster's behavior and preparing the secret super weapon. Due to high seismic activity and poor weather conditions the satellites haven't yet been able to make clear shots of the monster. The analysis of the first shot resulted in an undirected graph with $*n*$ vertices and $*m*$ edges. Now the world's best minds are about to determine whether this graph can be regarded as Cthulhu or not.

翻译中…

To add simplicity, let's suppose that Cthulhu looks from the space like some spherical body with tentacles attached to it. Formally, we shall regard as Cthulhu such an undirected graph that can be represented as a set of three or more rooted trees, whose roots are connected by a simple cycle.

翻译中…

It is guaranteed that the graph contains no multiple edges and self-loops.

翻译中…

image

翻译中…

Input

翻译中…

The first line contains two integers — the number of vertices $*n*$ and the number of edges $*m*$ of the graph ($1 ≤ *n* ≤ 100$, $0 ≤ *m* ≤$image).

翻译中…

Each of the following $*m*$ lines contains a pair of integers $*x*$ and $*y*$, that show that an edge exists between vertices $*x*$ and $*y*$ ($1 ≤ *x*, *y* ≤ *n*, *x* ≠ *y*$). For each pair of vertices there will be at most one edge between them, no edge connects a vertex to itself.

翻译中…

Output

翻译中…

Print "NO", if the graph is not Cthulhu and "FHTAGN!" if it is.

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Note

翻译中…

Let us denote as a simple cycle a set of $*v*$ vertices that can be numbered so that the edges will only exist between vertices number $1$ and $2$, $2$ and $3$, ..., $*v* - 1$ and $*v*$, $*v*$ and $1$.

翻译中…

A tree is a connected undirected graph consisting of $*n*$ vertices and $*n* - 1$ edges ($*n* > 0$).

翻译中…

A rooted tree is a tree where one vertex is selected to be the root.

翻译中…

样例

Input #1
6 6
6 3
6 4
5 1
2 5
1 4
5 4
Output #1
FHTAGN!
InputCopy OutputCopy
Input #2
6 5
5 6
4 6
3 1
5 1
1 2
Output #2
NO
InputCopy OutputCopy
题目信息
题号
104C
时间限制
2 s
内存限制
256 MB

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。