#include <stdio.h>

#define	CMAX	(100000)


typedef struct{
	int x;
	int y;
}POINT;


POINT coin[CMAX+5];

int main(void){
	int i,j,n;
	int cCnt=0;
	
	scanf("%d", &n);
	
	for(i=0;i<n;i++){
		int noHit=1;
		int tx, ty;
		scanf("%d %d", &tx, &ty);
		
		for(j=0;j<cCnt;j++){
			int len = (tx-coin[j].x)*(tx-coin[j].x) + (ty-coin[j].y)*(ty-coin[j].y);
			
			if(len < 20*20){
				printf("Hit %d %d\n",i, j);
				noHit = 0;
				break;
			}
		}
		if(noHit==1){
			coin[cCnt].x = tx;
			coin[cCnt].y = ty;
			cCnt += 1;
		}
	}
	
	printf("%d\n", cCnt);
	return 0;
}