#include<bits/stdc++.h>
using namespace std;
int wz,he;
double zl;
int main(){
	int n,t;
	cin>>n>>t;
	int a[n+1],b[n+1];
	double c[n+1];
	for(int i=1;i<=n;i++){
		cin>>a[i]>>b[i];
		c[i]=b[i]/a[i];
		
	}
	double maxx=0;
	for(int i1=1;i1<=n;i1++){
	for(int i=1;i<=n;i++){
		//cout<<1<<"　"; 
		if(c[i]>maxx){
			maxx=c[i];
			wz=i;
			}
					
	}
	//cout<<1<<" ";
	 
	if(he+a[wz]<=t){
		he=he+a[wz];
		zl=zl+b[wz];
	}else {
		zl=zl+(t-he)*c[wz];
		
		break;
	}maxx=0;
	c[wz]=0;
	}
	printf("%.2f",zl);
	return 0;
}

大佬们帮我看看