1094

/*
一个用来检查环，一个用来检查是否确定了排序
*/

// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>

#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>

using namespace std;

// typedef
typedef __int64 LL;

// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)

#define Z(a,b) ((a)<<(b))
#define Y(a,b) ((a)>>(b))

const double eps = 1e-6;
const double INFf = 1e100;
const int INFi = 1000000000;
const LL INFll = (LL)1<<62;
const double Pi = acos(-1.0);

template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
	if(x>y) return x;
	return y;
}
template<class T> inline T TMIN(T x,T y)
{
	if(x<y) return x;
	return y;
}
template<class T> inline T MMAX(T x,T y,T z)
{
	return TMAX(TMAX(x,y),z);
}
template<class T> inline T MMIN(T x,T y,T z)
{
	return TMIN(TMIN(x,y),z);
}
template<class T> inline void SWAP(T &x,T &y)
{
	T t = x;
	x = y;
	y = t;
}


// code begin
int N,M;
bool mp[26][26];
int in[26],in2[26];
char tmp[28];

int next()
{
	int cnt = 0,ans;
	for(int i=0;i<N;i++)
	{
		if(in2[i]==0)
		{
			cnt++;
			ans = i;
		}
	}
	if(cnt==1) return ans;
	return -1;
}
int next2()
{
	int ans;
	for(int i=0;i<N;i++)
		if(in2[i]==0)
			return i;
	return -1;
}

bool checksort(int dx)
{
	for(int i=0;i<N;i++) in2[i] = in[i];
	int head;
	for(int i=0;i<N;i++)
	{	
		head = next();
		if(head<0) return false;
		tmp[i] = head+'A';
		for(int j=0;j<N;j++)
		{
			if(mp[head][j])
			{
				in2[j]--;
			}
		}
		in2[head] = -1;
	}
	tmp[N] = 0;
	printf("Sorted sequence determined after %d relations: %s.\n",dx,tmp);
	return true;
}

int checkcircle()
{
	for(int i=0;i<N;i++) in2[i] = in[i];
	int head;
	for(int i=0;i<N;i++)
	{
		head = next2();
		if(head<0) return true;
		for(int j=0;j<N;j++)
			if(mp[head][j])
				in2[j]--;
		in2[head]=-1;
	}
	return false;
}

int main()
{
	read;
	write;
	int a,b,f,q;
	char strin[5];
	while(scanf("%d %d",&N,&M)==2)
	{

		if(N+M==0) break;
		memset(in,0,sizeof(in));
		memset(mp,0,sizeof(mp));
		f= 0;
		int i;
		for(i=1;i<=M;i++)
		{
			scanf("%s",strin);
			a = strin[0]-'A';
			b = strin[2]-'A';
			mp[a][b] = 1;
			in[b]++;
			if(checkcircle())
			{
				printf("Inconsistency found after %d relations.\n",i);
				f=1;break;
			}
			if(checksort(i))
			{
				f=1;break;
			}
		}
		for(i++;i<=M;i++) scanf("%s",strin);
		if(!f)
		{
			printf("Sorted sequence cannot be determined.\n");
		}

	}
	return 0;
}