#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<vector>
using namespace std;
using i32 = int_fast32_t;
using i64 = int_fast64_t;
#define rep(i, n) for (i32 i = 0; i < (i32)(n); i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
using P = pair<i64,i64>;

int main(){
ios::sync_with_stdio(false);
std::cin.tie(nullptr);
i32 n, m;
cin >> n >> m;
i32 now = 0;
i32 now_t = 0;
rep(i,m){
    i32 t,p;
    cin >> t >> p;
    if(t - now_t >= p - now){
        now_t = t;
        now = p;
    }else{
        cout << "No" << endl;
        return 0;
    }
}
cout << "Yes" << endl;
}