#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> P;
int INF = 1e18;
int mod = 1e9+7;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
signed main() {
    int N,M;
    cin >> N >> M;
    int old = 0,now = 0;
    for(int i = 0; i < M; i++) {
        int T,P;
        cin >> T >> P;
        if(abs(P-old) <= T-now) {
            old = P;now = T;
        }
        else {
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
}