#include<fstream>
using namespace std;
ifstream fin("energii.in");
ofstream fout("energii.out");
int n,g[1001],c[1001],p,o[1001],po;
float e[1001];
int main()
{int i,j,aux;
	fin>>n;
	fin>>p;
	for(i=1;i<=n;i++)
	{	fin>>g[i];
		fin>>c[i];
		e[i]=(float)g[i]/c[i];
		o[i]=i;
	}
	for(i=1;i<n;i++)
		for(j=i+1;j<=n;j++)
			if(e[o[i]]<e[o[j]])
			{
				aux=o[i];
				o[i]=o[j];
				o[j]=aux;
			}
	i=1;
	do{
		po=po+c[o[i]];
		p=p-c[o[i]];
		i++;
	}
	while(p>0&&i<=n);
	fout<<po;
}