#include <bits/stdc++.h>

using namespace std;

#define int long long
// #define DEBUG
#define x first
#define y second
#define File(a) freopen(a".in", "r", stdin); freopen(a".out", "w", stdout)

typedef long long ll;
typedef pair<int, int> PII;

const int N = 50005;
const int INF = 0x3f3f3f3f;

struct Node
{
	int idx, val;
	bool operator < (const Node &u) const { return val > u.val; };
};

int n, k, m, sum;
PII a[N];
bool vis[N];

priority_queue<int, vector<int>, greater<int>> heap;
priority_queue<Node> cost, disc;

bool cmp(PII a, PII b) { return a.y < b.y; }

signed main()
{
	// ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	
	cin >> n >> k >> m;
	for (int i = 1; i <= n; i ++)
		cin >> a[i].x >> a[i].y;
	sort(a + 1, a + 1 + n, cmp);
	
	for (int i = 1; i <= k; i ++)
	{
		sum += a[i].y;
		if (sum > m)
			return !printf("%d\n", i - 1);
		// vis[i] = true;
		heap.push(a[i].x - a[i].y);
		
		#ifdef DEBUG
		cout << sum << ' ';
		#endif
	}
	
	for (int i = k + 1; i <= n; i ++)
	{
		cost.push({i, a[i].x});
		disc.push({i, a[i].y});
	}
	
	for (int i = k + 1; i <= n; i ++)
	{
		#ifdef DEBUG
		cout << sum << ' ';
		#endif
		
		while (!cost.empty() && vis[cost.top().idx]) cost.pop();
		while (!disc.empty() && vis[disc.top().idx]) disc.pop();
		
		int costidx = INF, discidx = INF, par1 = INF, par2 = INF;
		if (!cost.empty()) costidx = cost.top().idx, par1 = cost.top().val;
		if (!disc.empty()) discidx = disc.top().idx, par2 = disc.top().val + heap.top();
		
		if (par1 > par2)
		{
			sum += par2;
			disc.pop(); heap.pop();
			heap.push({a[discidx].x - a[discidx].y});
			vis[discidx] = true;
		}
		else
		{
			sum += par1;
			cost.pop();
			vis[costidx] = true;
		}
		if (sum > m)
			return !printf("%d\n", i - 1);
	}
	cout << n << '\n';	
	
	return 0;
}