Little Susie listens to fairy tales before bed every day. Today's fairy tale was about wood cutters and the little girl immediately started imagining the choppers cutting wood. She imagined the situation that is described below.

There are n trees located along the road at points with coordinates x1, x2, ..., xn. Each tree has its height hi. Woodcutters can cut down a tree and fell it to the left or to the right. After that it occupies one of the segments [xi - hi, xi] or [xi;xi + hi]. The tree that is not cut down occupies a single point with coordinate xi. Woodcutters can fell a tree if the segment to be occupied by the fallen tree doesn't contain any occupied point. The woodcutters want to process as many trees as possible, so Susie wonders, what is the maximum number of trees to fell. 

Input

The first line contains integer n (1 ≤ n ≤ 105) — the number of trees.

Next n lines contain pairs of integers xi, hi (1 ≤ xi, hi ≤ 109) — the coordinate and the height of the і-th tree.

The pairs are given in the order of ascending xi. No two trees are located at the point with the same coordinate.

Output

Print a single number — the maximum number of trees that you can cut down by the given rules.

Examples

Input

5
1 2
2 1
5 10
10 9
19 1


Output

3


Input

5
1 2
2 1
5 10
10 9
20 1


Output

4

Note

In the first sample you can fell the trees like that: 

  * fell the 1-st tree to the left — now it occupies segment [ - 1;1]
  * fell the 2-nd tree to the right — now it occupies segment [2;3]
  * leave the 3-rd tree — it occupies point 5
  * leave the 4-th tree — it occupies point 10
  * fell the 5-th tree to the right — now it occupies segment [19;20]



In the second sample you can also fell 4-th tree to the right, after that it will occupy segment [10;19].
#include <bits/stdc++.h>
using namespace std;
bool cmp(vector<long long int> a, vector<long long int> b) {
  return a[0] > b[0];
}
bool sortfirst(pair<long long int, char> a, pair<long long int, char> b) {
  return a.first > b.first;
}
long long int gcd(long long int a, long long int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long int lcm(long long int a, long long int b) {
  return (a / gcd(a, b)) * b;
}
bool isPowerOfTwo(long long int n) {
  if (n == 0) return false;
  return (ceil(log2(n)) == floor(log2(n)));
}
double sumOfGP(double a, double r, long long int n) {
  double sum = 0;
  for (long long int i = 0; i < n; i++) {
    sum = sum + a;
    a = a * r;
  }
  return sum;
}
bool check(string s) {
  stack<char> st;
  for (long long int i = 0; i < s.length(); i++) {
    if (s[i] == '(')
      st.push('(');
    else {
      if (st.empty()) {
        return false;
      } else
        st.pop();
    }
  }
  if (st.empty())
    return true;
  else
    return false;
}
long long int mod = 1e9 + 7;
bool iszero(string a) {
  for (long long int i = 0; i < a.length(); i++) {
    if (a[i] == '1') return false;
  }
  return true;
}
long long int fac(long long int n) {
  if (n <= 0) return 1;
  return (n * fac(n - 1)) % mod;
}
long long int calSumGP(long long int a, long long int r, long long int n) {
  long long int sum = 0, temp = a % mod;
  for (long long int i = 1; i < n; i++) {
    sum = sum + temp;
    temp = (temp * r) % mod;
  }
  return sum % mod;
}
bool checksort(long long int a[], long long int n) {
  for (long long int i = 1; i < n; i++) {
    if (a[i] < a[i - 1]) return false;
  }
  return true;
}
long long int mxN = 1e6 + 5;
bool checksq(long long int n) {
  long long int t = sqrt(n);
  if (t * t == n) return true;
  return false;
}
long long int rec(long long int a[], long long int n, long long int i,
                  long long int sum) {
  long long int mx = 0;
  sum += a[i];
  if (i + 1 < n && sum >= 0) {
    for (long long int k = i + 1; k < n; k++) {
      if (k < n && sum + a[k] >= 0) mx = max(mx, (1 + rec(a, n, k, sum)));
    }
  }
  return mx;
}
bool checkPrime(long long int n) {
  for (long long int i = 2; i <= sqrt(n); i++)
    if (n % i == 0) return false;
  return true;
}
long long int countDigit(long long int n) { return floor(log10(n) + 1); }
const long long int size = 4e5 + 7;
vector<long long int> adj[size];
bool vis[size];
void dfs(int node) {
  vis[node] = true;
  for (auto it : adj[node]) {
    if (!vis[it]) dfs(it);
  }
}
void solve() {
  long long int n;
  cin >> n;
  vector<pair<long long int, long long int>> vp;
  while (n--) {
    long long int x, y;
    cin >> x >> y;
    vp.push_back({x, y});
  }
  if (vp.size() == 1) {
    cout << 1;
    return;
  }
  long long int cnt = 0;
  for (long long int i = 1; i + 1 < vp.size(); i++) {
    if ((vp[i].first - vp[i].second) > vp[i - 1].first) {
      cnt++;
    } else if ((vp[i].first + vp[i].second) < vp[i + 1].first) {
      cnt++;
      vp[i].first += vp[i].second;
    }
  }
  if (vp.size() >= 2) cnt += 2;
  cout << cnt;
}
int main() {
  solve();
  return 0;
}
