#include<bits/stdc++.h>
#define inf 0x7f7f7f
typedef long long ll;
typedef unsigned int ui;
typedef unsigned long long ull;
using namespace std;
inline int read()
{
    int x=0,f=1;char ch=getchar();
    for (;ch<'0'||ch>'9';ch=getchar())  if (ch=='-')    f=-1;
    for (;ch>='0'&&ch<='9';ch=getchar())   x=(x<<3)+(x<<1)+ch-'0';
    return x*f;
}
inline void print(int x)
{
    if (x>=10) print(x/10);
    putchar(x%10+'0');
}
const int N=1e4;
struct AC
{
    int l,r;
    void join(int x,int y){l=x,r=y;}
    bool operator <(const AC &x)const{return r<x.r;}
}A[N+10];
int main()
{
    int n=read();
    for (int i=1,x,y;i<=n;i++)   x=read(),y=read(),A[i].join(x,x+y);
    sort(A+1,A+1+n);
    int x=A[1].r,ans=1;
    for (int i=2;i<=n;i++)   if (A[i].l>=x)   x=A[i].r,ans++;
    printf("%d\n",ans);
    return 0;
}