#include <iostream>
#include <fstream>
#include <utility>
#include <vector>
using namespace std;
vector<pair<int, int> > Ob;
int nrGen, eNecesara, energ, cost, pMax, cMax, ok, cmin = 2000000000;

int main()
{
    freopen("energii.in", "rt", stdin);
    freopen("energii.out", "wt", stdout);
    scanf("%d%d", &nrGen, &eNecesara);
    Ob.push_back(make_pair(0, 0));
    for(int i=1; i<=nrGen; ++i)
    {
        scanf("%d\n%d", &energ, &cost);
        Ob.push_back(make_pair(cost, energ));
        cMax += cost;
    }
    vector<int>D(cMax+5);
    for(int o=1; o<=nrGen; ++o)
    {
        for( cost=cMax; cost>=0 ; --cost)
        {
            if(Ob[o].first <= cost)
                D[cost] = max(D[cost], (D[cost - Ob[o].first] + Ob[o].second) );
            if(D[cost] >= eNecesara && cost < cmin)
                cmin = cost;
        }
    }

    cout<<(cmin == 2000000000? -1 : cmin)<<'\n';
}