读一次数据判断一次
初始化state = 0；
1.当最深节点的深度 == 字符数时 找到 state = 1；
2.出现回路 state = -1；
#include <iostream>
#include <string>
using namespace std;

int state, map[26][26], deep[26];   //map存储有向边，deep存储深度

void updateDeep(int index, int value, int n)  //当父节点深度改变时更新子节点深度
{
	int i;

	deep[index] = value + 1;
	for (i = 0; i <= n; i++)
	{
		if (map[index][i] == 1)
		{
			updateDeep(i, deep[index], n);
		}
	}
}

void GoInto(int index, int i, int n)  //判断是否有回路的深度搜索函数
{
	int j;
	if (i == index)
	{
		state = -1;
		return;
	}

	for (j = 0; j <= n; j++)
	{
		if (map[i][j] == 1)
		{
			GoInto(index, j, n);
		}
	}

	return;
}

void IsCircle(int index, int n)    //判断是否有回路
{
	int i;

	for (i = 0; i <= n; i++)
	{
		if (map[index][i] == 1)
		{
			GoInto(index, i, n);
		}
	}
}

int Judge(int index, int n, char a, char c)    //判断状态
{
	int i, max;
	max = -1;

	IsCircle(index , n);

	if (state == -1)
	{
		return -1;
	}

	if (deep[a - 'A'] + 1 >= deep[c - 'A'])
	{
		updateDeep(c - 'A', deep[a - 'A'], n - 1);
	}

	for (i = 0; i <= n; i++)
	{
		if (max < deep[i])
		{
			max = deep[i];
		}
	}

	if (max == n)
	{
		return 1;
	}

	return 0;
}

string OutputSort(int n)   //按次序是出字符串
{
	string str;
	int i, j;

	str = "";

	for (i = 0; i <= n; i++)
	{
		for (j = 0; j <= n; j++)
		{
			if (deep[j] == i)
			{
				str += (j + 'A');
			}
		}
	}

	return str;
}

int main()
{
	int n, m, i, j, tm;
	char a, op, c;

	while (cin >> n >> m)
	{
		if (n == 0 && m == 0)
		{
			break;
		}

		//Initialize
		state = 0;
		tm = 0;
		for (i = 0; i < 26; i++)
		{
			deep[i] = 0;
			for (j = 0; j < 26; j++)
			{
				map[i][j] = 0;
			}
		}

		for (i = 1; i <= m; i++)
		{
			cin >> a >> op >> c;
			if (state == 1 || state == -1)
			{
				continue;
			}


			map[a - 'A'][c - 'A'] = 1;
			
			state = Judge(a - 'A', n - 1, a, c);
			if (state != 0)
			{
				tm = i;
			}
		}

		if (state == 0)
		{
			cout << "Sorted sequence cannot be determined." << endl;
		}
		else if (state == -1)
		{
			cout << "Inconsistency found after " << tm << " relations." << endl;
		}
		else if (state == 1)
		{
			cout << "Sorted sequence determined after " << tm << " relations:" << OutputSort(n - 1) << endl;
		}

	}
	return 0;
}