module xxx;

import std.stdio, std.bigint, std.conv, std.array, std.string, std.algorithm, std.typecons;

void main() {
    auto aa = readln().strip().split();
    auto n = to!int(aa[0]);
    auto s = BigInt(aa[1]);

    Tuple!(BigInt, string)[] m;

    for (int i = 0; i < n; i++) {
        auto a = readln().strip().split();
        auto name = a[0];
        auto num = BigInt(a[1]);
        m ~= tuple(num, name);
    }

    m.sort();

    string[] r;

    foreach_reverse(t; m) {
        if (s >= t[0]) {
            r ~= t[1];
            s -= t[0];
        }
    }

    if (s == 0) {
        writeln(r.length);

        foreach(name; r) {
            writeln(name);
        }
    } else {
        writeln(0);
    }
}