#include <iostream>
#include <fstream>
#include <cstring>
#define Maxx 10001
using namespace std;
struct genrator_curent
{
    int en,cost;
}A[Maxx];
ifstream fin("energii.in");
ofstream fout("energii.out");
int n,M,Dp[Maxx],i,cw;
int main()
{
    fin>>n>>M;
    for (i=1;i<=n;i++) fin>>A[i].en>>A[i].cost;
    for (i=1;i<=M;i++) Dp[i]=500001;
    for (i=1;i<=n;i++)
    {
        for (cw=M;cw>=0;cw--)
        {
            if (A[i].en+cw<M)
                Dp[A[i].en+cw]=min(Dp[A[i].en+cw],Dp[cw]+A[i].cost);
            else
                Dp[M]=min(Dp[M],Dp[cw]+A[i].cost);
        }
    }
    fout<<Dp[M];
    return 0;
}