#include <stdio.h>
#include <stdlib.h>

int x,y,dir,step;/* top, right, bot, left */
int i,*startx, *starty, *endx, *endy;

int check_top(int in) {
	int i;
	for(i=1;i<step-1;i+=2) {
		if(starty[i] >= y && starty[i] <= y+in && startx[i] <= x && endx[i] >= x) {
			return 1;
		}
	}
	return 0;
}

int check_bot(int in) {
	int i;
	for(i=1;i<step-1;i+=2) {
		if(starty[i] >= y-in && starty[i] <= y && startx[i] <= x && endx[i] >= x) {
			return 1;
		}
	}
	return 0;
}

int check_left(int in) {
	int i;
	for(i=0;i<step-1;i+=2) {
		if(startx[i] >= x-in && startx[i] <= x && starty[i] <= y && endy[i] >= y) {
			return 1;
		}
	}
	return 0;
}

int check_right(int in) {
	int i;
	for(i=0;i<step-1;i+=2) {
		if(startx[i] >= x && startx[i] <= x+in && starty[i] <= y && endy[i] >= y) {
			return 1;
		}
	}
	return 0;
}

int fce(int inst) {
x=0;y=0;dir=0;step=0;
		startx = malloc(inst*sizeof(int));
		starty = malloc(inst*sizeof(int));
		endy = malloc(inst*sizeof(int));
		endx = malloc(inst*sizeof(int));
		for(i = 0; i<inst;i++) {
			int in;
			scanf("%d", &in);
			if(dir == 0) {
				if(check_top(in)) {
					printf("%d\n", step);
					free(endx);
					free(endy);
					free(startx);
					free(starty);
					return inst-step-1;
				}
				startx[step] = x;
				starty[step] = y;
				endx[step] = x;
				endy[step] = y+in;
				y = y+in;
			}
			else if(dir == 1) {
				if(check_right(in)) {
					printf("%d\n", step);
					free(endx);
					free(endy);
					free(startx);
					free(starty);
					return inst-step-1;
				}
				startx[step] = x;
				starty[step] = y;
				endx[step] = x+in;
				endy[step] = y;
				x = x+in;
			}
			if(dir == 2) {
				if(check_bot(in)) {
					printf("%d\n", step);
					free(endx);
					free(endy);
					free(startx);
					free(starty);
					return inst-step-1;
				}
				startx[step] = x;
				starty[step] = y-in;
				endx[step] = x;
				endy[step] = y;
				y = y-in;
			}
			if(dir == 3) {
				if(check_left(in)) {
					printf("%d\n", step);
					free(endx);
					free(endy);
					free(startx);
					free(starty);
					return inst-step-1;
				}
				startx[step] = x-in;
				starty[step] = y;
				endx[step] = x;
				endy[step] = y;
				x = x-in;
			}
			step++;
			dir = (dir+1)%4;
		}
		printf("OK\n");		
		free(endx);
		free(endy);
		free(startx);
		free(starty);
		return 0;

}

int main() {
	int inst;
	while(scanf("%d", &inst) == 1) {
		int j,tmp2,tmp =fce(inst);
		for(j=0;j<tmp;j++)scanf("%d", &tmp2);
	}

	return 0;
}