#include <fstream>

using namespace std;
ifstream f("energii.in");
ofstream g("energii.out");
struct asd{
    int g,p;
}a[1010];
long long d[10000008],N,G,i,j,s;
int main()
{
    f >> N >> G;
    for(i = 1; i <= N; i++){
        f >> a[i].p >> a[i].g;
        s += a[i].g;
    }
    for(i = 1; i <= N; i++){
        for(j = s; j >= a[i].g; j--){
            d[j] = max(d[j],d[j-a[i].g] + a[i].p);
        }
    }
    for(i = 1; i <= s; i++){
        if(d[i] >= G){
            g << i;
            return 0;
        }
    }
    g << -1;
    return 0;
}