This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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;
pint a[maxn], b[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);
    }
    for (int i=0; i<n; i++) {
        while (k and b[k-1].y <= a[i].y) k--;
        if (!k or b[k-1].x < a[i].x) b[k++] = a[i];
    }
    cout << k << '\n';
}
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