#include<iostream.h>
#include<fstream.h> 
long p,c,h, n,min=5002,aux,aux1,v[100],v1[100],gasit=1,s,ok,i;
int main()
{ifstream f("energii.in");
ofstream g("energii.out");
f>>n>>h;

for(i=1;i<=n;i++)
{f>>v[i]>>v1[i];
}
while(gasit)
{gasit=0;
for(i=1;i<n;i++)
if(v1[i]/v[i]>v1[i+1]/v[i+1])
{aux1=v1[i];
aux=v[i];
v1[i]=v1[i+1];
v[i]=v[i+1];
v1[i+1]=aux1;
v[i+1]=aux;
gasit=1;}
}    
/*for(i=1;i<=n;i++)
g<<v1[i]<<"\n"; */
s=0;i=1;
while(s<h)
{s=s+v1[i];
i++;}

g<<s;
f.close();
g.close();
return 0;
}