#include<stdio.h>
int main()
{
    int a[100] , b[100];
    int i , j , n , m;
    int count[100] = {0};
    scanf("%d %d",&n,&m);
    for(i = 1;i <= m;i++)
    {
        scanf("%d %d",&a[i],&b[i]);
        for(j = a[i];j <= b[i];j++)
        count[j]++;
    }
    for(i = 1;i <= n;i++)
    {
        if(count[i] != 1)
        {
            printf("%d %d",i,count[i]);
            return 0;
        }
    }
    printf("OK");
    return 0;
}