#include<cstdio>

#include<algorithm>

using namespace std;

int n,f[10001];

struct Point{int x,y;}p[10001];

bool operator < (const Point &a,const Point &b){return a.x<b.x;}

int main()

{

    scanf("%d",&n);

    for(int i=1;i<=n;++i) scanf("%d%d",&p[i].x,&p[i].y);

    sort(p+1,p+1+n);

    for(int i=1;i<=n;++i) f[i]=1;

    for(int i=1;i<=n;++i)

      for(int j=1;j<i;++j)

        if(p[j].x+p[j].y<=p[i].x)

          f[i]=max(f[j]+1,f[i]);

    printf("%d\n",*max_element(f+1,f+n+1));

    return 0;

}