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#include <bits/stdc++.h>

#define ll long long
#define LIM 300005
#define X first
#define Y second
#define EL cout<<"\n"

using namespace std;

pair <int, int> a[LIM];

int n;
ll k;

bool check(int x)
{
	ll cnt = 0;

	for (int i = n; i >= 1; i--)
		if (a[i].X >= x)
		{
			cnt += a[i].Y;
		}
		else break;

	return (cnt <= k);
}

int BNS()
{
	int l = 1, r = 1e9 + 1;

	while (l <= r)
	{
		int mid = (l + r) / 2;

		if (l == mid || mid == r)
		{
			for (int i = l; i <= r; i++)
				if (check(i)) return i;
			return 0;
		}

		if (check(mid)) r = mid;
		else l = mid;
	}

	return 0;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
    freopen("TASK.INP", "r", stdin);
    freopen("TASK.OUT", "w", stdout);
    #endif

    cin >> n >> k;

    for (int i = 1; i <= n; i++)
    	cin >> a[i].X >> a[i].Y;

    sort(a + 1, a + 1 + n);

    cout << BNS();

    return 0;
}