快调哭了

#include<bits/stdc++.h>
using namespace std;
int n,t;
int i;
double b;
struct qm{
	double jz,zl;
	double dj;
}stu[105];
bool cmp(qm x,qm y){
	return x.dj>y.dj;
}
int main(){
    cin>>n>>t;
    double a=t;
    for(i=0;i<n;i++){
    	cin>>stu[i].zl>>stu[i].jz;
    	stu[i].dj=stu[i].jz/stu[i].zl;
	}
	sort(stu,stu+n,cmp);
	for(i=0;;i++){
		if(a<stu[i].zl) break;
		a-=stu[i].zl;
		b+=stu[i].jz;
	}
	b+=a/stu[i].zl*stu[i].jz;
	printf("%.2f",b);
}