#include <bits/stdc++.h>

using namespace std;

vector<string> split_string(string);

// Complete the luckBalance function below.
int luckBalance(int k, vector<vector<int>> contests) {

    int out;
    cout << contests[0][0] << contests [0][1] << endl;

    int imp = 0;
    //cout << contests.size() << endl; 6
    int sum = 0;
    vector<int> vect(contests.size(), 0);
    for (int i = 0 ; i< contests.size(); i++){
        imp = imp + contests[i][1];
        sum = sum + contests[i][0];
        vect[i] = contests[i][1];
    }
    //cout << imp << endl;

    if (imp < k) {
        return sum;
    }
    bool cont = 1;
    while(cont){

        idxs =



    }


    return out;

}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string nk_temp;
    getline(cin, nk_temp);

    vector<string> nk = split_string(nk_temp);

    int n = stoi(nk[0]);

    int k = stoi(nk[1]);

    vector<vector<int>> contests(n);
    for (int i = 0; i < n; i++) {
        contests[i].resize(2);

        for (int j = 0; j < 2; j++) {
            cin >> contests[i][j];
        }

        cin.ignore(numeric_limits<streamsize>::max(), '\n');
    }

    int result = luckBalance(k, contests);

    fout << result << "\n";

    fout.close();

    return 0;
}

vector<string> split_string(string input_string) {
    string::iterator new_end = unique(input_string.begin(), input_string.end(), [] (const char &x, const char &y) {
        return x == y and x == ' ';
    });

    input_string.erase(new_end, input_string.end());

    while (input_string[input_string.length() - 1] == ' ') {
        input_string.pop_back();
    }

    vector<string> splits;
    char delimiter = ' ';

    size_t i = 0;
    size_t pos = input_string.find(delimiter);

    while (pos != string::npos) {
        splits.push_back(input_string.substr(i, pos - i));

        i = pos + 1;
        pos = input_string.find(delimiter, i);
    }

    splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));

    return splits;
}