#include <bits/stdc++.h>
using namespace std;
struct resident {
int x, e, canBeRoot;
};
const int MAX_N = 5e5;
const int INF = 1e9 + 1;
resident r[MAX_N + 1];
int main() {
int n;
cin >> n;
for ( int i = 1; i <= n; i++ ) {
cin >> r[i].x >> r[i].e;
r[i].canBeRoot = true;
}
sort( r + 1, r + 1 + n, []( resident a, resident b ) {
if ( a.x == b.x )
return a.e > b.e;
return a.x < b.x;
} );
int maxLeft = -INF;
for ( int i = 1; i <= n; i++ ) {
if ( r[i].x + r[i].e > maxLeft )
maxLeft = r[i].x + r[i].e;
else
r[i].canBeRoot = false;
}
sort( r + 1, r + 1 + n, []( resident a, resident b ) {
if ( a.x == b.x ) {
if ( a.e == b.e )
return a.canBeRoot < b.canBeRoot;
return a.e < b.e;
}
return a.x < b.x;
} );
int minRight = INF;
for ( int i = n; i >= 1; i-- ) {
if ( r[i].x - r[i].e < minRight )
minRight = r[i].x - r[i].e;
else
r[i].canBeRoot = false;
}
int ans = 0;
for ( int i = 1; i <= n; i++ )
ans += r[i].canBeRoot;
cout << ans << "\n";
}
