#include <bits/stdc++.h>
using namespace std;
bool myfnc(const pair<int, int>& a, const pair<int, int>& b) {
  return a.second > b.second;
}
bool myfnc1(const pair<int, int>& a, const pair<int, int>& b) {
  return a.first > b.first;
}
bool triple(const tuple<int, int, int>& a, const tuple<int, int, int>& b) {
  if (get<1>(a) == get<1>(b)) return get<0>(a) < get<0>(b);
  return get<1>(a) < get<1>(b);
}
template <typename K, typename V>
void print_map(std::map<K, V> const& m) {
  for (auto const& pair : m) {
    std::cout << pair.first << ":" << pair.second << "\n";
  }
}
const int inf = 1e5 + 10;
void lockdown() {
  int n, m;
  cin >> n >> m;
  int x, y;
  int a[105];
  memset(a, 0, sizeof(a));
  for (int i = 0; i < m; i++) {
    cin >> x >> y;
    for (int j = x; j <= y; j++) a[j]++;
  }
  for (int i = 1; i <= n; i++) {
    if (a[i] == 0 || a[i] > 1) {
      cout << i << " " << a[i];
      return;
    }
  }
  cout << "OK"
       << "\n";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    lockdown();
  }
  return 0;
}
