#include <cstdio>

#include <vector>

#include <queue>

using namespace std;



typedef vector<int> vi;



int main() {

    int V, E, u, v;

    vector<vi> AdjList;



    while (scanf("%d", &V), V) {

        AdjList.assign(V, vi());

        scanf("%d", &E);



        for (int i = 0; i < E; i++) {

            scanf("%d %d", &u, &v);

            AdjList[u].push_back(v);

            AdjList[v].push_back(u);

        }



        queue<int> q;

        q.push(0);

        vi color(V, 1e9);

        color[0] = 0;

        bool isBipartite = true;

        while (!q.empty() && isBipartite) {

            int u = q.front();

            q.pop();

            for (int j = 0; j < (int) AdjList[u].size(); j++) {

                int v = AdjList[u][j];

                if (color[v] == 1e9) {

                    color[v] = 1 - color[u];

                    q.push(v);

                } else if (color[v] == color[u]) {

                    isBipartite = false;

                    break;

                }

            }

        }



        if (isBipartite)

            printf("BICOLORABLE.\n");

        else

            printf("NOT BICOLORABLE.\n");

    }



    return 0;

}