An ascending sorted sequence of distinct values is one in which some form of a less-than operator is used to order the elements from smallest to largest. For example, the sorted sequence A, B, C, D implies that A < B, B < C and C < D. in this problem, we will give you a set of relations of the form A < B and ask you to determine whether a sorted order has been specified or not.

Input consists of multiple problem instances. Each instance starts with a line containing two positive integers n and m. the first value indicated the number of objects to sort, where 2 <= n <= 26. The objects to be sorted will be the first n characters of the uppercase alphabet. The second value m indicates the number of relations of the form A < B which will be given in this problem instance. Next will be m lines, each containing one such relation consisting of three characters: an uppercase letter, the character "<" and a second uppercase letter. No letter will be outside the range of the first n letters of the alphabet. Values of n = m = 0 indicate end of input.

For each problem instance, output consists of one line. This line should be one of the following three:

Sorted sequence determined after xxx relations: yyy...y. 
Sorted sequence cannot be determined. 
Inconsistency found after xxx relations.

where xxx is the number of relations processed at the time either a sorted sequence is determined or an inconsistency is found, whichever comes first, and yyy...y is the sorted, ascending sequence.

4 6

A<B

A<C

B<C

C<D

B<D

A<B

3 2

A<B

B<A

26 1

A<Z

0 0

Sorted sequence determined after 4 relations: ABCD.

Inconsistency found after 2 relations.

Sorted sequence cannot be determined.
代码：

#include<cstdio>

#include<iostream>

#include<cstring>

#include<algorithm>

#include<queue>

#include<stack>

#include<vector>

#include<map>

#include<cmath>

const int maxn=1e5+;

typedef long long ll;

using namespace std;

vector<int>vec[];

int n,m;

int du[];

int chu[];

int du1[];

int flag;

vector<int>ans1;

void Tpsort()

{

    priority_queue<int,vector<int>,greater<int> >q;

    priority_queue<int>q1;

    int s=;

    for(int t=;t<n;t++)

    {

        if(chu[t]==&&du[t]==)

        {

         s=;

        }

    }

    for(int t=;t<n;t++)

    {

        du1[t]=du[t];

    }

    for(int t=;t<n;t++)

    {

        if(du1[t]==)

        {

            q.push(t);

            q1.push(t);

        }

    }

    vector<int>ans,ans2;

    while(!q.empty())

    {

        int now=q.top();

        int now2=q1.top();

        q.pop();

        q1.pop();

        ans.push_back(now);

        ans2.push_back(now2);

        for(int t=;t<vec[now].size();t++)

        {

            int next=vec[now][t];

            du1[next]--;

            if(du1[next]==)

            {

                q.push(next);

                q1.push(next);

            }

        }

    }

    if(ans.size()!=n)

    {

        flag=;

    }

//    cout<<ans.size()<<" "<<s<<endl;

    if(ans.size()==n&&s==)

    {

        int sss=;

        for(int t=;t<ans.size();t++)

        {

            if(ans[t]!=ans2[t])

            {

                sss=;

            }

        }

        if(sss==)

        {

            flag=;

            for(int t=;t<ans.size();t++)

            {

                ans1.push_back(ans[t]);

            }

        }

    }

}

int main()

{ 

   while(cin>>n>>m)

   {

    if(n==&&m==)

    {

        break;

    }

    for(int t=;t<n;t++)

    {

        vec[t].clear();

    }

       char str[];

       memset(du,,sizeof(du));

       memset(chu,,sizeof(chu));

       flag=;

       int ss=;

       int k;

       ans1.clear();

       for(int t=;t<=m;t++)

       {

           scanf("%s",str);

           vec[str[]-'A'].push_back(str[]-'A');

           du[str[]-'A']++;

           chu[str[]-'A']++;

           if(ss)

           {

           continue;

        }

           Tpsort();

           if(flag==)

           {

               printf("Inconsistency found after %d relations.\n",t);

               ss=;

        }

        else if(flag==)

        {

            ss=;

            printf("Sorted sequence determined after %d relations: ",t);

            for(int j=;j<n;j++)

            {

                printf("%c",ans1[j]+'A');

            }

            printf(".\n");

        }

    }

    if(ss==)

    puts("Sorted sequence cannot be determined.");

   }

   return ;

}