#include <fstream>

using namespace std;
int i,j,n,G,sol;
int v[5005],w[5005],m[10005];
int main()
{
    ifstream f("energii.in");
    ofstream g("energii.out");

    f>>n>>G;
    for(i=1;i<=n;i=i+1)
    {
        f>>w[i];
        f>>v[i];
    }
    for(i=0;i<=G;i=i+1)
        m[i]=20000;

    for(i=1;i<=n;i++)
    for(j=G;j>=0;j--)
        if(w[i]>=j)
            m[j]=min(m[j],v[i]);

        if(m[G]!=20000)
    g<<m[G];

    else
        g<<-1;


    return 0;
}