#include<iostream>
#include<algorithm>
using namespace std;
struct Stu{
int have;
int need;
int lack;
};
bool cmp(Stu a,Stu b){
return a.lack<b.lack;
}
int main(){
int m,n;
cin>>m;
Stu s[11000];
while(m--){
cin>>n;
for(int i=0;i<n;i++){
cin>>s[i].have>>s[i].need;
s[i].lack=s[i].need-s[i].have;
}
sort(s,s+n,cmp);
int sum=0;
int flag=1;
for(int i=0;i<n;i++){
if(s[i].lack<=0){//积木足够
sum+=s[i].have;
}else{
if(sum+s[i].have>=s[i].need){
sum+=s[i].have;
}else{
flag=0;
}
}
}
if(flag==1){
cout<<"YES"<<endl;
}else{
cout<<"NO"<<endl;
}
}
return 0;
}