Kampanja Unfinished

#include <bits/stdc++.h>

using namespace std;

bool sorting(pair<int, int> a, pair<int, int> b) {
    if (a.first == b.first) {
        if (a.second > b.second) return true;
        else return false;
    } else if (a.first < b.first)
        return true;
    return false;
}

int main()
{
    int n, c;
    cin >> n >> c;

    vector<  pair<int, int>  > diff;
    for (int i = 0; i < c; ++i) {
        int p, r;
        cin >> p >> r;

        diff.push_back(make_pair(p - r, p));
    }

    sort(diff.begin(), diff.end(), sorting);

    int COUNT = 0;
    for (int i = 0; i < diff.size(); ++i) {

        // IF THE YOU CAN GO TO THAT CITY, GO THERE :D
        if (n - diff[i].second >= 0) {
            n -= diff[i].first;

            COUNT++;
        }
    }

    cout << COUNT << endl;

    return 0;
}