#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m;
    if (!(cin >> n >> m)) return 0;
    vector<vector<int>> adj(n + 1);
    vector<int> in_degree(n + 1, 0);
    for (int i = 0; i < m; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        in_degree[v]++;
    }
    queue<int> q;
    for (int i = 1; i <= n; i++) {
        if (in_degree[i] == 0) q.push(i);
    }
    int cnt = 0;
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        cnt++;
        for (int v : adj[u]) {
            in_degree[v]--;
            if (in_degree[v] == 0) q.push(v);
        }
    }
    if (cnt == n) {
        cout << "DAG\n";
    } else {
        cout << "CYCLE\n";
    }
    return 0;
}