#include <cstdlib>
#include <iostream>

using namespace std;

const int sz = 1000000;
const int maxNumber = 10000;

int arr[sz];
int counting[maxNumber + 1];

void countingSort(int *arr, int l, int r) {
    for (int value=0; value<=maxNumber; value++) counting[value] = 0;

    for (int i=l; i<=r; i++) counting[arr[i]]++;

    for (int value=0; value<=maxNumber; value++) {
        while (counting[value]) {
            arr[l++] = value;
            counting[value]--;
        }
    }
}

bool check() {
    for (int i=0; i<sz-1; i++){
        if (arr[i] > arr[i + 1]) return false;
    }
    return true;
}

int main(){
    for (int i=0; i<sz; i++) {
        arr[i] = rand() % maxNumber;
    }

    countingSort(arr, 0, sz - 1);

    cout<<(check() ? "OK": "FAIL");

    return 0;
}