#include<stdio.h>
#define MAX 100001


int main(void){
    
    int i,n,m,t[MAX],p[MAX],now = 0,nowt =0;

    scanf("%d %d",&n,&m);
    for(i=0;i<m;i++){
        scanf("%d %d",&t[i],&p[i]);
        //printf("%d %d\n",t[i],p[i]);
    }
    i=0;
    while(1){
        //printf("t[ %d ] - nowt = %d",i,t[i]-nowt);
        if(t[i]-nowt < p[i] - now) {
            printf("No\n");
            break;
        }
        nowt = t[i];
        now = p[i];
        i++;
        if(i >= m){
            printf("Yes\n");
            break;
        }
    }
    return 0;
}