#include<set>
#include<cmath>
#include<cstdio>
#include<iostream>
#include<algorithm>

using namespace std;

#define N 50001

int line;

struct Line
{
    int id,xi;
}e[N<<1];

int lev[N];

bool equal(double a,double b)
{
    return abs(a-b)<1e-7;
}

struct Circle
{
    int x,y,r;
    
    double gety(int f)
    {
        double dy=sqrt(1.0*r*r-1.0*(line-x)*(line-x));
        return y+dy*f;
    }
        
}cir[N];

struct Node
{
    int id,tag;
    
    Node(){}
    Node(int id_,int tag_) : id(id_),tag(tag_) {}
    
    bool operator < (const Node p) const
    {
        double ya=cir[id].gety(tag),yb=cir[p.id].gety(p.tag);
        if(!equal(ya,yb)) return ya>yb;
        return tag>p.tag;
    }

};

set<Node>s; 

bool cmp(Line p,Line q)
{
    return p.xi<q.xi;
}

int main()
{
    int n,m,k,ld,rd,ans;
    set<Node>:: iterator l,r;
    while(scanf("%d",&n)!=EOF)
    {
        m=0;
        for(int i=0;i<n;++i) 
        {
             scanf("%d%d%d",&cir[i].x,&cir[i].y,&cir[i].r);
             e[++m].id=i;
             e[m].xi=cir[i].x-cir[i].r;
            e[++m].id=i+n;
            e[m].xi=cir[i].x+cir[i].r;
        }
        sort(e+1,e+m+1,cmp);
        for(int i=1;i<=m;++i)
        {
            k=e[i].id%n;
            line=e[i].xi;
            if(e[i].id<n)
            {
                s.insert(Node(k,1));
                l=s.lower_bound(Node(k,1));
                r=l;
                r++;
                if(l==s.begin() || r==s.end()) lev[e[i].id]=1;
                else
                {
                    l--;
                    ld=(*l).id;
                    rd=(*r).id;
                    if(ld==rd) lev[e[i].id]=lev[ld]+1;
                    else lev[e[i].id]=max(lev[ld],lev[rd]);
                }
                s.insert(Node(k,-1));
            }
            else
            {
                s.erase(Node(k,1));
                s.erase(Node(k,-1));
            }
        }
        ans=0;
        for(int i=0;i<n;++i) ans=max(ans,lev[i]);
        printf("%d\n",ans);
    }
    return 0;
}