#include <cstdio>#include <cstring>#include <stack>#include <iostream>using namespace std;#define N 1005int first[N] , in[N] , rec[N] , vis[N] , k;char str[N][5];struct Node{    int y , next;}node[N<<1];void add_edge(int x,int y){    in[y]++;    node[k].y = y , node[k].next = first[x];    first[x] = k++;}int dag(int cnt , int n){    int copy_in[N];    for(int i = 0 ; i<n ; i++) copy_in[i] = in[i];    int t = 0;    stack<int> s;    for(int i = 0 ; i<n ; i++){        if(!copy_in[i] && vis[i])        {          //  cout<<"there: "<<i<<" "<<cnt<<" "<<n<<endl;            t++;            s.push(i);        }    }    int flag = 1;    for(int i = 0 ; i<cnt ; i++){        if(s.empty()){            return -1;        }        if(s.size() > 1) flag = 0;        int u = s.top();        s.pop();        rec[i] = u;        for(int i=first[u] ; i!=-1 ; i=node[i].next){            int v = node[i].y;            copy_in[v]--;            if(!copy_in[v]) s.push(v);        }    }    if(cnt == n && t == 1 && flag) return 1;    else return 0;}int main(){  //  freopen("a.in" , "rb" , stdin);    int n,m,a,b;    while(~scanf("%d%d",&n,&m)){        if(n==0 && m==0) break;        memset(first , -1 , sizeof(first));        memset(in , 0 , sizeof(in));        memset(vis , 0 , sizeof(vis));        for(int i = 0 ; i<m ; i++){            scanf("%s",str[i]);        }        int cnt = 0;//计算当前传入的所有边中含有的点数        k=0;        for(int i=0 ; i<m ; i++){            //add edge            a = str[i][0] - ‘A‘;            if(!vis[a]){                cnt++;                vis[a]=1;            }            b = str[i][2] - ‘A‘;            if(!vis[b]){                cnt++;                vis[b]=1;            }          //  cout<<"here: "<<a<< " "<<b<<endl;            add_edge(a,b);            int falg = dag(cnt , n);            if(falg == -1)            {                printf("Inconsistency found after %d relations.\n" , i+1);                break;            }            else if(falg == 1)            {                printf("Sorted sequence determined after %d relations: " , i+1);                for(int i=0;i<n;i++)                {                    char c = ‘A‘+rec[i];                    cout<<c;                }                printf(".\n");                break;            }            else{                if(i<m-1) continue;                printf("Sorted sequence cannot be determined.\n");            }        }    }    return 0;}