/*DFS , bipartite graph*/






#include<iostream>
#include<cstring>
using namespace std;
#define size 205
int matrix[size][size];
int color[size];
int n = 0;

int dfs(int start) {

 for (int end= 0; end < n; end++)
 {
  //matirx[start][end] = 1 , means start vertex and end vertex was connected
  if (matrix[start][end])
  {
   //if end vertex hasn't be check, then drew color and keep going next adjacent vertex
   if (!color[end]) {
    color[end] = !color[start];
    dfs(end);
   }

  // based on end vertex has been check before
  // start vertex and end vertex color have the same color, means color already repeat ,so cant be drew correct
   else if (color[start] == color[end])
    return 0;
  }
 }
 return 1;
}

int main(void) {

 while (1)
 {
  int l = 0,row=0,col=0;
  cin >> n;

  if (n == 0)break;
  cin >> l;

  memset(matrix, 0, sizeof(matrix));
  memset(color, 0, sizeof(color));
    /*
  1: connected and colored
  0: disconncted and uncolored
 */
  for (int i = 0; i < l; i++)
  {
   cin >> row >> col;
   matrix[row][col] = matrix[col][row] = 1;
  }
  color[0] = 1;
  if (dfs(0))
  cout<<"BICOLORABLE." <<endl;
  else
  cout << "NOT BICOLORABLE."<< endl;

 }

}