#include <stdio.h>

int main()
{
	unsigned int pocet;
	unsigned int prew2;
	unsigned int prew;
	unsigned int cislo, i, path = 0;
	int ok = 1;
		

	while(scanf("%d", &pocet) != EOF)
	{
		ok = 1;
		if(pocet <= 3)
		{
			for(i = 0; i < pocet; i++)
			{
				scanf("%d", &cislo);
			}
			printf("OK\n");
			continue;
		}

		scanf("%d %d", &prew2, &prew); 
		path = 2;
		for(i = 0; i < pocet-2; i++)
		{
			scanf("%d", &cislo);
			if(ok != 0)
			{
			path++;
				if (cislo > prew2) {
				prew2 = prew;
				prew = cislo;
				} else if (cislo <= prew2) {
						if (cislo >= prew){
							ok = 0;
						}
				}


			}
		}
		if (ok)
			printf("OK\n");
		else
			printf("%d\n", path);
	}

	return 0;
}