int main(){
	int i,n,gy[100],dy[100],zc[100],e,s,k,max=0;
	scanf("%d",&n);
	for(i=0;i<n;i++){
         scanf("%d%d",&gy[i],&dy[i]);
		 if(gy[i]>=90&&gy[i]<=140&&dy[i]>=60&&dy[i]<=90){
			 zc[i]=1;
		 }else{zc[i]=0;}
	}
    for(i=0;i<n;i++){
        if((i==0||zc[i-1]==0)&&zc[i]==1){e=i;}
		if((i==n-1||zc[i+1]==0)&&zc[i]==1){s=i;}
        if(s>=e){
			k=s-e+1;
			if(k>max){max=k;}
		}
	}
	printf("%d",max);
	return 0;
}