#include<fstream>
#include<iostream>
#include<climits>
#include<algorithm>
#include<cstring>
#include<cmath>

using namespace std;

//ifstream f("in.in");
//ofstream g("out.out");

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

int d[20005],energie[10005],greutate[10005];
int indiceMaxim = 0,n,G;

int main()
{
    f>>n;
    f>>G;
    d[0]=0;

    for(int i=1;i<=n;i++){
        f>>energie[i]>>greutate[i];
    }

    for(int i=1;i<=20000;i++)
        d[i]=-1;

    for(int i=1;i<=n;i++){
        for(int j=indiceMaxim;j>=0;j--){
            if(d[j]!=-1){
                if(d[energie[i]+j]!=-1)
                    d[energie[i]+j] = min(d[j] + greutate[i],d[energie[i]+j]);
                else
                    d[energie[i]+j] = d[j] + greutate[i];

                indiceMaxim = max(indiceMaxim,min(G,energie[i]+j));
            }
        }
    }
    int mini = INT_MAX;
    for(int i=20000;i>=G;i--){
        if(d[i]!=-1)
        {
            mini = min(mini,d[i]);
        }
    }
    if(mini == INT_MAX)
        g<<-1;
    else
        g<<mini;

    //for(int i=0;i<=20000;i++)
        //cout<<d[i]<<'\n';
    f.close();
    g.close();
    return 0;
}