#include <bits/stdc++.h>
#define sz(v) ((int)(v).size())
using namespace std;
typedef long long lint;
typedef pair<int, int> pi;
const int MAXN = 10000005;
static char buf[1 << 19]; // size : any number geq than 1024
static int idx = 0;
static int bytes = 0;
static inline int _read() {
if (!bytes || idx == bytes) {
bytes = (int)fread(buf, sizeof(buf[0]), sizeof(buf), stdin);
idx = 0;
}
return buf[idx++];
}
static inline int _readInt() {
int x = 0, s = 1;
int c = _read();
while (c <= 32) c = _read();
if (c == '-') s = -1, c = _read();
while (c > 32) x = 10 * x + (c - '0'), c = _read();
if (s < 0) x = -x;
return x;
}
int n;
pi a[MAXN];
vector<int> stk;
bool in(int x, int y){
return a[x].first - a[x].second <= a[y].first - a[y].second &&
a[y].first + a[y].second <= a[x].first + a[x].second;
}
int main(){
n = _readInt();
for(int i=0; i<n; i++){
a[i].first = _readInt();
a[i].second = _readInt();
if(stk.empty()) stk.push_back(i);
else{
if(in(stk.back(), i)) continue;
while(!stk.empty() && in(i, stk.back())) stk.pop_back();
stk.push_back(i);
}
}
printf("%d\n", sz(stk));
}
