#include <bits/stdc++.h>
using namespace std;
using lint = long long;
using pint = pair<lint, lint>;
#define x first
#define y second
const int maxn = 10000004;
int n, k, b[maxn];
pint a[maxn];
//https://www.geeksforgeeks.org/fast-io-for-competitive-programming/
void fastscan(int &number)
{
//variable to indicate sign of input number
bool negative = false;
register int c;
number = 0;
// extract current character from buffer
c = getchar();
if (c=='-')
{
// number is negative
negative = true;
// extract the next character from the buffer
c = getchar();
}
// Keep on extracting characters if they are integers
// i.e ASCII Value lies from '0'(48) to '9' (57)
for (; (c>47 && c<58); c=getchar())
number = number *10 + c - 48;
// if scanned input has a negative sign, negate the
// value of the input number
if (negative)
number *= -1;
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
fastscan(n);
for (int i=0; i<n; i++) {
int x, y;
fastscan(x); fastscan(y);
a[i] = pint(x+y, y-x);
}
sort(a, a+n);
reverse(a, a+n);
n = unique(a, a+n, [](pint x, pint y) { return x.x == y.x; }) - a;
reverse(a, a+n);
for (int i=0; i<n; i++) {
while (k and b[k-1] <= a[i].y) k--;
b[k++] = a[i].y;
}
cout << k << '\n';
}
