#include <bits/stdc++.h>
using namespace std;
int INF = 1000000005;
long long INFF = 1000000000000000005LL;
int main() {
  long long s, n;
  cin >> s >> n;
  long long x, y;
  vector<pair<long long, long long>> strengths;
  for (long long i = 0; i < n; i++) {
    cin >> x >> y;
    strengths.push_back(make_pair(x, y));
  }
  sort(strengths.begin(), strengths.end());
  bool win = true;
  for (long long i = 0; i < n; i++) {
    if (s <= strengths[i].first) {
      win = false;
      break;
    }
    s += strengths[i].second;
  }
  if (win) {
    cout << "YES"
         << "\n";
    ;
  } else {
    cout << "NO"
         << "\n";
    ;
  }
  return 0;
}
