int main(){
	int sz[101];
	int n,i,t=0,q,s=-1;
	int xy[100][2];
	scanf("%d",&n);
	for(i=0;i<n;i++){
	     scanf("%d %d",&xy[i][0],&xy[i][1]);
	}
	for(i=0;i<n;i++){
		if(xy[i][0]>=90&&xy[i][0]<=140&&xy[i][1]>=60&&xy[i][1]<=90){
			t++;
		}
		if(xy[i+1][0]<90||xy[i+1][0]>140||xy[i+1][1]<60||xy[i+1][1]>90){
			s++;
			sz[s]=t;
			t=0;
		}
	}
	for(i=0;i<s;i++){
		if(sz[i]>sz[i+1]){
			q=sz[i];
			sz[i]=sz[i+1];
			sz[i+1]=q;
		}
	}
	printf("%d",sz[s]);
	return 0;
}




				

