#include <iostream>
#include <string>
#include <cstring>
#include <cstdio>
#include <map>
#define INF 100000000
#define MAX 40 

using namespace std ;


double dis[MAX],graph[MAX][MAX];
bool Bellman_Ford(int n)
{
	for(int i = 0 ; i <= n ; ++i)
	{
		dis[i] = 0.0;
	}
	dis[0] = 1 ;
	for(int i = 0 ; i < n-1 ; ++i)
	{
		for(int j = 0 ; j < n ; ++j)
		{
			for(int k = 0 ; k < n ; ++k)
			{
				if(graph[k][j] > 0.000001)
				{
					if(dis[j] < dis[k]*graph[k][j])
					{
						dis[j] = dis[k]*graph[k][j] ;
					}
				}
			}
		}
	}
	for(int i = 0 ; i < n ; ++i)
	{
		for(int j = 0 ; j < n ; ++j)
		{
			if(dis[i] < dis[j]*graph[j][i])	//只要有一个存在即可。 
			{
				return true ;
			}
		}
	}
	return false ;
}

int main()
{
	int n , m , c = 1 ; 
	double rate ;
	map<string,int> search;
	string nameA,nameB,temp ;
	while(cin>>n && n)
	{
		for(int i = 0 ; i < n ; ++i)
		{
			cin>>temp ;
			search.insert(pair<string,int>(temp,i));
		}
		cin>>m;
		memset(graph,0,sizeof(graph)) ;
		for(int j = 0 ; j < m ; ++j)
		{
			cin>>nameA>>rate>>nameB;
			int x = search[nameA] , y = search[nameB] ;
			graph[x][y] = rate ;
		}
		if(Bellman_Ford(n))
		{
			printf("Case %d: Yes\n",c++);
		}
		else
		{
			printf("Case %d: No\n",c++);
		}
		search.clear() ;
	}
	return 0 ;
}

<pre name="code" class="cpp">#include <iostream>
#include <string>
#include <cstring>
#include <cstdio>
#include <map>
#define INF 100000000
#define MAX 40 

using namespace std ;


double graph[MAX][MAX];
bool Floyd(int n)
{
	for(int k = 0 ; k < n ; ++k)
	{
		for(int i = 0 ; i < n ; ++i)
		{
			for(int j = 0 ; j < n ; ++j)
			{
				if(graph[i][j] < graph[i][k]*graph[k][j])
					graph[i][j] = graph[i][k]*graph[k][j] ;
			}
		}
	}
	for(int i = 0 ; i < n ; ++i)
	{
		if(graph[i][i]>1)
		{
			return true ;
		}
	}
	return false ;
}

int main()
{
	int n , m , c = 1 ; 
	double rate ;
	map<string,int> search;
	string nameA,nameB,temp ;
	while(cin>>n && n)
	{
		memset(graph,0,sizeof(graph)) ;
		for(int i = 0 ; i < n ; ++i)
		{
			cin>>temp ;
			search.insert(pair<string,int>(temp,i));
			graph[i][i] = 1 ;
		}
		cin>>m;
		for(int j = 0 ; j < m ; ++j)
		{
			cin>>nameA>>rate>>nameB;
			int x = search[nameA] , y = search[nameB] ;
			graph[x][y] = rate ;
		}
		if(Floyd(n))
		{
			printf("Case %d: Yes\n",c++);
		}
		else
		{
			printf("Case %d: No\n",c++);
		}
		search.clear() ;
	}
	return 0 ;
}