#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 123;
const int MINN = 1e3 + 123;
const int mod = 1e9 + 7;
const int INF = 1e9 + 1;
pair<int, int> a[MINN];
bool cmp(pair<int, int> a, pair<int, int> b) {
  if (a.first < b.first) return 1;
  if (a.first == b.first)
    if (a.second > b.second) return 1;
  return 0;
}
int main() {
  int n, sum;
  cin >> sum >> n;
  for (int i = 1; i <= n; i++) scanf("%d%d", &a[i].first, &a[i].second);
  sort(a + 1, a + n + 1, &cmp);
  for (int i = 1; i <= n; i++) {
    if (sum <= a[i].first) {
      cout << "NO";
      return 0;
    }
    sum += a[i].second;
  }
  cout << "YES";
  return 0;
}
