#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for(int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    ll n, m;
    cin >> n >> m;
    int flag = 1;
    ll now = 0;
    ll time = 0;
    rep(i,m){
        ll a, b;
        cin >> a >> b;
        if(abs(now-b) > a - time) flag = 0;
        time = a;
        now = b;
    }
    if(flag)yn;
    return 0;
}