题解

留个点赞和关注在走吧！

#include<bits/stdc++.h>
using namespace std;
int n,m;
struct asdf{
	int a,b,c;
}a[130];
bool cmp(asdf a,asdf b){
	return a.c>b.c;
}
int main(){
	cin>>n>>m;
	int sum=0;
	for(int i=1;i<=n;i++){
		cin>>a[i].a>>a[i].b;
		a[i].c=a[i].a-a[i].b;
		sum+=a[i].a;
	}
	sum-=m;
	sort(a+1,a+1+n,cmp);
	int num=0;
	while(sum>0&&num<n){
		num++;
		sum-=a[num].c;
	}
	if(sum>0){
		cout<< -1;
		return 0;
	}
	cout<<num;
	return 0;
}