#include <iostream>

#include <fstream>

using namespace std;

ifstream in("energii.in");
ofstream out("energii.out");

const int N=5002;
int profit[N],p[N/5],c[N/5];
int n,maxim=1000000,gr,cmax;

int main()

{

    in>>n>>gr;

    for(int i=0; i<n; ++i)
    {
        in>>c[i]>>p[i];
        cmax=max(cmax,c[i]);
    }

    profit[0]=0;
    for(int i=1; i<=gr+cmax; ++i) profit[i]=100000000;

    for(int i=0; i<n; ++i)
    {
        for(int j=gr-c[i]; j>=0; --j)
            if(profit[j]!=-1 && profit[j]+p[i]<profit[j+c[i]])
                profit[j+c[i]]=profit[j]+p[i];
    }
    for(int i=gr; i<=gr+cmax; ++i)
        maxim=min(maxim,profit[i]);
    out<<maxim;

    return 0;

}