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#include<bits/stdc++.h>
#define DilligentArch() ios_base::sync_with_stdio(false); cin.tie(0),cout.tie(0);
#define testcase(t) int t; cin>>t; while(t--)
#define pb push_back
typedef long long ll;
using namespace std;
const int N = 1e5+10;
vector<int>g[N];
int clr[N];
bool vis[N];
ll v,e;

bool checkdfs(int vertex) {

    if(clr[vertex]==-1)clr[vertex]=1;
    //vis[vertex] = true;
    for(int child : g[vertex]) {
        //if(vis[child])
        //continue;
        if(clr[child]==-1) {
            clr[child]=1-clr[vertex];
            if(!checkdfs(child)) return false;
        }
        else if(clr[child]==clr[vertex]) return false;

    }
    return true;
}

bool checkbi() {
    memset(clr,-1,sizeof(clr));
    for(ll i=0; i<v; i++) {
        if(clr[i]==-1) {
            if(!checkdfs(i))return false;

        }
    }
    return true;
}

void solve()
{

    cin>>v;
    if(v==0)return;
    cin>>e;

    // memset(vis,0,sizeof(vis));
    for(ll i=0; i<e; i++) {
        ll x,y;
        cin>>x>>y;
        g[x].pb(y);
        g[y].pb(x);
    }


    if(checkbi())cout<< "BICOLORABLE."<<endl;
    else cout<< "NOT BICOLORABLE."<<endl;



}

int main()

{

    while(1) {
        solve();
        memset(clr,-1,sizeof(clr));
    }

}