#include <bits/stdc++.h>
#define st first
#define nd second
#define mp make_pair
#define pb push_back
#define coc g[mode][i]
#define sol (k+k)
#define sag (k+k+1)
#define orta ((bas+son)>>1)
#define mod 1000000007
#define inf 1000000009
#define N 5000005
using namespace std;
typedef long long ll;
typedef pair < int , int > ii;
typedef pair < double , double > dd;
int n, m, result;
char ch;
ii a;
stack < ii > s;
int readInt () {
result = 0;
while (true) {
ch = getchar();
if (ch < '0' || ch > '9') break;
result = result*10 + (ch - '0');
}
return result;
}
int main(){
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
n = readInt();
for(int i = 1; i <= n; i++){
// scanf("%d %d",&a.st ,&a.nd);
a.st = readInt();
a.nd = readInt();
while(!s.empty() and abs(s.top().st - a.st) <= a.nd - s.top().nd)
s.pop();
if(!s.empty() and abs(s.top().st - a.st) <= s.top().nd - a.nd)
continue;
s.push(a);
}
printf("%d\n", (int)s.size());
return 0;
}
