//#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
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[N+1][5*N+1];
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=5*N;j>=c[i];--j)
            dp[i][j] = max(dp[i-1+!i][j],e[i]+dp[i-1][j-c[i]]);
    }
    for(int i=0;i<=5*N;++i) if(dp[n-1][i]>=E){ // aici era gresit, pana la 5*N nu N
        cout << i;
        return 0;
    }
    cout << -1;
    printf("\nTime taken: %.2fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
}