#include <iostream>
#include <vector>
#include <cassert>
#include <queue>


using namespace std;

class Graph {
public:
    struct Edge {
        int target_vertex, next_edge;
    };

    vector<Edge> edges;
    vector<int> head_edges;

    void init(int vertices_amount, int edges_amount = 1) {
        edges.reserve(edges_amount);
        head_edges.resize(vertices_amount, -1);
    }

    void add_edge(int source_vertex, int target_vertex) {
        edges.push_back({target_vertex, head_edges[source_vertex]});
        head_edges[source_vertex] = static_cast<int>(edges.size()) - 1;
    }

    void remove_edge(int source_vertex, int target_vertex) {
        for (int edge = head_edges[source_vertex]; edge != -1; edge = edges[edge].next_edge) {
            if (edges[edge].target_vertex == target_vertex) {
                head_edges[source_vertex] = edges[edge].next_edge;
                // edges.erase(edges.begin() + edge);
                break;
            }
        }
    }

    [[nodiscard]] bool accessible(int source_vertex, int target_vertex) const {
        vector<bool> visited(head_edges.size(), false);
        queue<int> q;
        q.push(source_vertex);
        visited[source_vertex] = true;
        while (!q.empty()) {
            int current_vertex = q.front();
            q.pop();
            for (int edge = head_edges[current_vertex]; edge != -1; edge = edges[edge].next_edge) {
                int next_vertex = edges[edge].target_vertex;
                if (next_vertex == target_vertex) {
                    return true;
                }
                if (!visited[next_vertex]) {
                    visited[next_vertex] = true;
                    q.push(next_vertex);
                }
            }
        }
        return false;
    }

    [[nodiscard]] bool cycled(int source_vertex) const {
        return accessible(source_vertex, source_vertex);
    }
};

int letters_amount, edges_amount;
Graph graph;

void add_edge_by_string(const string& s) {
    assert(s.length() == 3);
    graph.add_edge(s[0] - 'A', s[2] - 'A');
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> letters_amount >> edges_amount;
    graph.init(letters_amount, edges_amount);

    return 0;
}