#include <bits/stdc++.h>
using namespace std;
const int inf = 1 << 28;
const double INF = 1e12, EPS = 1e-9;
int n, m, c[101];
void run() {
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    for (; a <= b; a++) c[a]++;
  }
  for (int i = 1; i <= n; i++)
    if (c[i] != 1) {
      cout << i << " " << c[i] << endl;
      return;
    }
  cout << "OK" << endl;
}
int main() { run(); }
