#include <cstdio>

#include <cstring>

#include <cmath>

#include <string>

#include <iostream>

#include <algorithm>

#include <queue>

#include <set>

#include <vector>

#include <map>

using namespace std;

typedef long long ll;

#define pii pair<int, int>

#define mkpii make_pair<int, int>

#define pdi pair<double, int>

#define mkpdi make_pair<double, int>

#define pli pair<ll, int>

#define mkpli make_pair<ll, int>

#define rep(i, n) for(int i=0; i<(n); ++i)

#define for1(i,a,n) for(int i=(a);i<=(n);++i)

#define for2(i,a,n) for(int i=(a);i<(n);++i)

#define for3(i,a,n) for(int i=(a);i>=(n);--i)

#define for4(i,a,n) for(int i=(a);i>(n);--i)

#define CC(i,a) memset(i,a,sizeof(i))

#define read(a) a=getint()

#define print(a) printf("%d", a)

#define dbg(x) cout << (#x) << " = " << (x) << endl

#define error(x) (!(x)?puts("error"):0)

#define printarr2(a, b, c) for1(_, 1, b) { for1(__, 1, c) cout << a[_][__]; cout << endl; }

#define printarr1(a, b) for1(_, 1, b) cout << a[_] << '\t'; cout << endl

inline const ll getint() { ll r=0, k=1; char c=getchar(); for(; c<'0'||c>'9'; c=getchar()) if(c=='-') k=-1; for(; c>='0'&&c<='9'; c=getchar()) r=r*10+c-'0'; return k*r; }

inline const int max(const int &a, const int &b) { return a>b?a:b; }

inline const int min(const int &a, const int &b) { return a<b?a:b; }

const int N=300005;

struct dat { ll l, r; }a[N];

const bool cmp(const dat &a, const dat &b) { return a.l==b.l?a.r>b.r:a.l<b.l; }

int n, s[N], top, fa[N];

ll sum[N];

int main() {

	read(n);

	for1(i, 1, n) { int x=getint(), r=getint(); a[i].l=x-r; a[i].r=x+r; }

	sort(a+1, a+1+n, cmp);

	for1(i, 1, n) {

		while(top && a[s[top]].r<a[i].r) --top;

		fa[i]=s[top];

		s[++top]=i;

	}

	for1(i, 1, n) sum[fa[i]]+=a[i].r-a[i].l;

	int ans=n+1;

	for1(i, 1, n) if(sum[i]==a[i].r-a[i].l) ++ans;

	printf("%d\n", ans);

	return 0;

}