#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;
}
