#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("unroll-loops,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
inline int readInt() {
int x = 0;
char ch = getchar();
while (ch < '0' || ch > '9') ch = getchar();
while (ch >= '0' && ch <= '9'){
x = (x << 3) + (x << 1) + ch - '0';
ch = getchar();
}
return x;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
n = readInt();
vector <pair<int,int>> arr(n);
for (int z=0;z<n;z++){
arr[z].first = readInt();
arr[z].second = readInt();
int t = arr[z].first;
arr[z].first -= arr[z].second;
arr[z].second += t;
}
stack <pair<int,int>> s;
for (int z=0;z<n;z++){
if (s.empty()){
s.push(arr[z]);
}
if (s.top().first <= arr[z].first && arr[z].second <= s.top().second) continue;
else{
while (arr[z].first <= s.top().first && s.top().second <= arr[z].second){
s.pop();
if (s.size() == 0) break;
}
s.push(arr[z]);
}
}
printf("%d",int(s.size()));
}
