Description：

Solution：

Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<stack>

#include<cstring>

using namespace std;

int testcases;

int n,m;

#define MAXN 110

#define MAXM 1010

struct edge

{

	int to,nxt;

}e[(MAXM * 2) << 1];

int edgenum = 0;

int lin[MAXN << 2] = {0};

void add(int a,int b)

{

	++edgenum;e[edgenum].to = b;e[edgenum].nxt = lin[a];lin[a] = edgenum;

	return;

}

stack<int> s;

int dfn[MAXN << 1],low[MAXN << 1],tot = 0;

bool v[MAXN << 1];

int scc = 0,ins[MAXN << 1];

void tarjan(int k)

{

	dfn[k] = low[k] = ++tot;

	v[k] = true;s.push(k);

	for(int i = lin[k];i != 0;i = e[i].nxt)

	{

		if(dfn[e[i].to] == 0)

		{

			tarjan(e[i].to);

			low[k] = min(low[k],low[e[i].to]);

		}

		else if(v[e[i].to])

		{

			low[k] = min(low[k],dfn[e[i].to]);

		}

	}

	if(low[k] == dfn[k])

	{

		int t;

		++scc;

		do

		{

			t = s.top();s.pop();

			v[t] = false;ins[t] = scc;

		}while(t != k);

	}

	return;

}

char getc()

{

	char c = getchar();

	while(c != 'h' && c != 'm')c = getchar();

	return c;

}

int read()

{

	int res = 0;

	char c = getchar();

	while(!isdigit(c))c = getchar();

	while(isdigit(c))

	{

		res = (res << 1) + (res << 3) + c - '0';

		c = getchar();

	}

	return res;

}

void work()

{

	memset(lin,0,sizeof(lin));

	edgenum = 0;

	tot = 0;

	memset(dfn,0,sizeof(dfn));

	memset(low,0,sizeof(low));

	memset(ins,0,sizeof(ins));

	memset(v,0,sizeof(v));

	scc = 0;

	scanf("%d%d",&n,&m);

	int k1,k2,type1,type2;

	for(int i = 1;i <= m;++i)

	{

		type1 = (getc() == 'h' ? 0 : 1);

		k1 = read();

		type2 = (getc() == 'h' ? 0 : 1);

		k2 = read();

		add((k1 - 1) * 2 + (type1 ^ 1),(k2 - 1) * 2 + type2);

		add((k2 - 1) * 2 + (type2 ^ 1),(k1 - 1) * 2 + type1);

	}

	for(int i = 0;i < 2 * n;++i)

	{

		if(dfn[i] == 0)

		{

			tarjan(i);

		}

	}

	bool found = false;

	for(int i = 1;i <= n;++i)

	{

		if(ins[(i - 1) * 2 + 1] == ins[(i - 1) * 2 + 0])

		{

			found = true;

			break;

		}

	}

	if(found)puts("BAD");

	else puts("GOOD");

	return;

}

int main()

{

	scanf("%d",&testcases);

	for(int i = 1;i <= testcases;++i)

		work();

	return 0;

}