#include <iostream>
#include <set>
#include <vector>
#include <algorithm>
using namespace std;
const int N = (1<<19) + 1;
int X[N], E[N], sg1[N<<1], sg2[N<<1];
void insert(int i, int xme, int xpe, int cur = 1, int st = 1, int en = N){
if (i >= en or i < st)
return;
if (en - st == 1){
sg1[cur] = xme;
sg2[cur] = xpe;
return;
}
int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
insert(i, xme, xpe, lc, st, mid);
insert(i, xme, xpe, rc, mid, en);
sg1[cur] = max(sg1[lc], sg1[rc]);
sg2[cur] = min(sg2[lc], sg2[rc]);
}
int get1(int i, int v1, int cur = 1, int st = 1, int en = N){
if (en - st == 1)
return st;
int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
if (sg1[lc] >= v1)
return get1(i, v1, lc, st, mid);
if (i >= mid)
return get1(i, v1, rc, mid, en);
return 0;
}
int get2(int i, int v2, int cur = 1, int st = 1, int en = N){
if (en - st == 1)
return st;
int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
if (sg2[rc] <= v2)
return get2(i, v2, rc, mid, en);
if (i < mid)
return get2(i, v2, lc, st, mid);
return 0;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(NULL);
for (int i=1;i<(N<<1);i++)
sg1[i] = -2.1e9, sg2[i] = 2.1e9;
int n, Ans = 0, cur;
cin>>n;
set<pair<int,int>> st0, st1;
vector<pair<int,int>> vec(n);
for (int i=1, x, e;i<=n;i++){
cin>>x>>e;
vec[i-1] = {x, e};
}
sort(vec.begin(), vec.end());
for (int i=1;i<=n;i++){
X[i] = vec[i-1].first, E[i] = vec[i-1].second;
st1.insert({E[i], i});
insert(i, X[i] - E[i], X[i] + E[i]);
}
while (st1.size() > 0){
if (st0.size() > 0 and ((*rbegin(st1)).first <= (*rbegin(st0)).first) ) {
cur = (*rbegin(st0)).second;
st0.erase({E[cur], cur});
}
else{
Ans++;
cur = (*rbegin(st1)).second;
st1.erase({E[cur], cur});
}
// cout<<" "<<Ans<<" "<<cur<<endl;
while (1){
int g = get1(cur, X[cur] - E[cur]);
if (g == 0)
break;
insert(g, -2.1e9, 2.1e9);
// cout<<" - "<<g<<endl;
st1.erase({E[g], g});
st0.insert({E[g], g});
}
while (1){
int g = get2(cur, X[cur] + E[cur]);
if (g == 0)
break;
// cout<<" + "<<g<<endl;
insert(g, -2.1e9, 2.1e9);
st1.erase({E[g], g});
st0.insert({E[g], g});
}
}
cout<<Ans<<'\n';
}
