// Template
#include <bits/stdc++.h>
#define rep_override(x, y, z, name, ...) name
#define rep2(i, n) for (int i = 0; i < (int)(n); ++i)
#define rep3(i, l, r) for (int i = (int)(l); i < (int)(r); ++i)
#define rep(...) rep_override(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define per(i, n) for (int i = (int)(n) - 1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
constexpr int inf = 1001001001;
constexpr ll INF = 3003003003003003003;
template <typename T> inline bool chmin(T& x, const T& y) {if (x > y) {x = y; return 1;} return 0;}
template <typename T> inline bool chmax(T& x, const T& y) {if (x < y) {x = y; return 1;} return 0;}
struct IOSET {IOSET() {cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(10);}} ioset;

// Main
int main() {
    int n, m;
    cin >> n >> m;
    vector<int> t(m);
    vector<ll> p(m);
    rep(i, m) cin >> t[i] >> p[i];
    
    int now = 0;
    ll tim = 0;
    rep(i, m) {
        if (abs(p[i] - now) > t[i] - tim) {
            cout << "No\n";
            return 0;
        }
        tim = t[i]; now = p[i];
    }
    cout << "Yes\n";
    return 0;
}