#include <fstream>

using namespace std;
int d[50005];
ifstream fin("energii.in");
ofstream fout("energii.out");
int main()
{
    int n,g,i,p,c,j,mi=1000005;
    fin>>n>>g;
    for(i=1;i<=g;++i){
        d[i]=-1;
    }
    for(i=1;i<=n;++i){
        fin>>c>>p;
        for(j=g;j>=g-c;--j){
            if(d[j]!=-1 && d[j]+p<mi){
                mi=d[j]+p;
            }
        }
        for(j=g-c-1;j>=0;--j){
            if(d[j]!=-1 && (d[j+c]==-1 || d[j+c]>d[j]+p)){
                d[j+c]=d[j]+p;
            }
        }
    }

    fout<<mi;
    return 0;
}