Keep the Customer Satisfied

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <vector>
#include <string>
#include <cctype>
#include <complex>
#include <cassert>
#include <utility>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
typedef pair<int,int> PII;
typedef long long ll;
#define lson l,m,rt<<1
#define pi acos(-1.0)
#define rson m+1,r,rt<<11
#define All 1,N,1
#define read freopen("in.txt", "r", stdin)
const ll  INFll = 0x3f3f3f3f3f3f3f3fLL;
const int INF= 0x7ffffff;
const int mod =  1000000007;
struct node{
    int q,d;
}a[800010];
int n;
bool cmp(node x,node y){
    return x.d<y.d;
}
void solve(){
    sort(a,a+n,cmp);
    int sum=0,num=0;
    priority_queue<int>que;
    for(int i=0;i<n;++i){
        if(sum+a[i].q>a[i].d){
            if(que.empty())continue;
            int tmp=que.top();
                if(tmp>a[i].q){
                    sum=sum+a[i].q-tmp;
                    que.pop();
                    que.push(a[i].q);
                }
        }
        else{
                num++;
            que.push(a[i].q);
            sum+=a[i].q;
        }
    }
    printf("%d\n",num);
}
int main()
{
    int t,ca=0;
    scanf("%d",&t);
    while(t--){
            if(ca++)
            printf("\n");
        scanf("%d",&n);
        for(int i=0;i<n;++i)
            scanf("%d%d",&a[i].q,&a[i].d);
        solve();
    }
return 0;
}