#include <bits/stdc++.h>
using namespace std;
int main() {
//	freopen("001.phase1.full.input", "r", stdin), freopen("out.txt", "w", stdout);
//	freopen("in.txt", "r", stdin);
	int n, m;
	cin >> n >> m;
	vector<int> deg(n);
	vector<vector<int>> e(n);
	vector<vector<int>> g(n, vector<int>(n));
	for (int i = 0, u, v; i < m; i++) {
		cin >> u >> v;
		u--;
		v--;
		e[u].push_back(v);
		e[v].push_back(u);
		g[u][v] = g[v][u] = 1;
		deg[u]++, deg[v]++;
	}
	for (int u = 0; u < n; u++) {
		int sz = e[u].size();
		for (int i1 = 0; i1 < sz; i1++) {
			int u1 = e[u][i1];
			for (int i2 = 0; i2 < i1; i2++) {
				int u2 = e[u][i2];
				for (int i3 = 0; i3 < i2; i3++) {
					int u3 = e[u][i3];
					for (int i4 = 0; i4 < i3; i4++) {
						int u4 = e[u][i4];
						if (g[u1][u2] && g[u1][u3] && g[u1][u4] && g[u2][u3] && g[u2][u4] && g[u3][u4]) {
							cout << "ok" << "\n";
							return 0;
						}
					}
				}
			}
		}
	}
	cout << "mark" << "\n";
	vector<int> id(n);
	iota(id.begin(), id.end(), 0);
	auto cmp = [&](int i, int j) {
		return deg[i] > deg[j];
	};
	sort(id.begin(), id.end(), cmp);
	for (auto &l : e) {
		sort(l.begin(), l.end(), cmp);
	}
	vector<int> st, ins(n);
	function<void(int)> dfs = [&](int u) {
		if (ins[u]) return;
		st.push_back(u);
		if (st.size() == 5) {
			int num = 0;
			for (int i = 0; i < 5; i++) {
				for (int j = 0; j < i; j++) {
					num += g[st[i]][st[j]];
				}
			}
			if (num >= 5) {
				vector<array<int, 2>> edges;
				for (int i = 0; i < 5; i++) {
					for (int j = 0; j < i; j++) {
						if (!g[st[i]][st[j]]) {
							edges.push_back({st[i], st[j]});
						}
					}
				}
				cout << edges.size() << "\n";
				for (auto [x, y] : edges) {
					cout << x + 1 << " " << y + 1 << "\n";
				}
				exit(0);
			}
			st.pop_back();
			return;
		}
		ins[u] = 1;
		for (int v : e[u]) {
			dfs(v);
		}
		ins[u] = 0;
		st.pop_back();
	};
	for (int S : id) {
		dfs(S);
	}
	return 0;
}