//#include <iostream>
#include <cstdio>
#include <algorithm>
#include <time.h>
#include <queue>
#include <cmath>
#include <stack>
#include <fstream>
#include <bitset>
#include <set>

using namespace std;
#define nl '\n'
#define all(v) v.begin(),v.end()
#define eb(x) emplace_back(x)
#define ull unsigned long long
#define File "energii""."
#define N 1002
#define M 10003
ifstream cin(File"in");
ofstream cout(File"out");

template<class a, class type>
void print(a v, type t) {
    for_each(all(v), [](type x) { cout << x << ' '; });
    cout << nl;
}

int n, E, e[N], c[N];
int dp[M + 7];

int main() {
    ios_base::sync_with_stdio(false);
    clock_t tStart = clock();
    cin >> n >> E;
    for (int i = 0; i < n; ++i) {
        cin >> e[i] >> c[i];
    }
    for (int i = 0; i < n; ++i) {
        for (int j = M; j >= c[i]; --j)
            dp[j] = max(dp[j], e[i] + dp[j - c[i]]);
    }
    for (int i = 0; i <= M; ++i)
        if (dp[i] >= E) {
            cout << i;
            printf("\nTime taken: %.2fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
            return 0;
        }
    cout << -1;
    printf("\nTime taken: %.2fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
}