#include <fstream>
using namespace std;
ifstream fin("energii.in");
ofstream fout("energii.out");
const int NMAX = 10011005;
int N, W, Max, Gmax, Cmin, ok;
int P[NMAX], G[NMAX], Sol[NMAX];
int main()
{
fin >> N >> W;
for(int i = 1; i <= N; i++)
fin >> P[i] >> G[i], Gmax += G[i];
for(int i = 1; i <= N; i++) {
for(int j = Gmax - G[i]; j >= 0; j--) {
if(Sol[j + G[i]] < Sol[j] + P[i])
Sol[j + G[i]] = Sol[j] + P[i];
}
}
for(int i = 1; i <= Gmax; i++)
if(Sol[i] >= W) {
fout << i << '\n';
return 0;
}
fout << "-1" << '\n';
return 0;
}