#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>

using namespace std;

struct Coord {
	Coord(int x = 0, int y = 0) : x(x), y(y) {}
	
	bool operator<(const Coord & r) const
	{
		if(x != r.x) return x < r.x;
		else return y < r.y;
	}
	
	bool operator==(const Coord & r) const
	{
		return (x == r.x) && (y == r.y);
	}

	int x;
	int y;
};

void move(vector<Coord> & coords, int & a, int & b, int dir, int steps)
{
	for(int i = 0; i < steps; i++)
	{
		switch(dir)
		{
		case 0:
			b += 1;
			break;
		case 1:
			a += 1;
			break;
		case 2:
			b -= 1;
			break;
		default:
			a -= 1;
			break;
		}
	
		Coord c(a, b);
		coords.push_back(c);
	}
}

int main(void)
{
	do
	{
		vector<Coord> coords;
		//coords.insert(Coord(0, 0));
	
		string str;
		getline(cin, str);
		
		if(str.length() == 0) break;
		
		int n, dir = 0, a = 0, b = 0, count = 0;
		sscanf(str.c_str(), "%d", &n);
		
		for(int i = 0; i < n; i++)
		{
			int steps;
			scanf(" %d ", &steps);
			
			move(coords, a, b, dir, steps);
			
			dir = (dir + 1) % 4;
		}
		
		sort(coords.begin(), coords.end());
		for(unsigned int i = 0; i < coords.size()-1; i++)
			if(coords[i] == coords[i+1]) count++;
		
		if(count) cout << n-count << endl;
		else cout << "OK" << endl;
	}
	while(cin.good());

	return 0;
}