#include <bits/stdc++.h>

using namespace std;

ifstream fin ("energii.in");
ofstream fout ("energii.out");

int n, E, c[1002], v[1002], s, s2;
int dp[1001][20000], mnn;

void Read()
{
    fin >> n >> E;

    for(int i = 1; i <= n; i++)
    {
        fin >> v[i] >> c[i];
        s += v[i];
        s2 += c[i];
        mnn = min(c[i], mnn);
    }
    if( s < E)
    {
        fout << "-1\n";
        exit(0);
    }
    if(s == E)
    {
        fout << s2 << "\n";
        exit(0);
    }
}

void Solve()
{
    int mn = 99999999;
    dp[1][c[1]] = v[1];
    for(int i = 2; i <= n; i++)
        for(int j = mnn; j <= 10005; j++)
        {
            dp[i][j] = dp[i - 1][j];
            if(j - c[i] >= 0)
                if(dp[i][j], dp[i - 1][j - c[i]] + v[i])
                    dp[i][j] = dp[i - 1][j - c[i]] + v[i];
                if(dp[i][j] >= E && mn > j)
                    mn = j;
        }
    fout << mn;
}

int main()
{
    Read();
    Solve();
    return 0;
}