//
//  na 2639.cpp
//  Competitive Programming
//
//  Created by m2 on 2024/11/27.
//

#include <stdio.h>
#include <iostream>
#include <random>
#include <set>
typedef long long int ll;
const ll inf = 0x1fffffffffffffff;
using namespace std;
const int maxn = 5e4 + 5;
int n, k, w[maxn], q[maxn], d[maxn], qs;
ll S, cost;
template<typename T> inline void rd(T &v){
    v = 0; char r = getchar();
    while(r - 48 >= 10u)
        r = getchar();
    while(r - 48 < 10u){
        v = (v << 3) + (v << 1) + (r ^ 48);
        r = getchar();
    }
}
template<typename T> void pd(T v){
    if(v < 10)
        putchar(int(v) ^ 48);
    else{
        pd(v / 10);
        putchar(int(v % 10) ^ 48);
    }
}
struct CmpD{
    inline bool operator()(const int &a, const int &b) const{
        return d[a] == d[b]? a < b: d[a] < d[b];
    }
};
struct CmpW{
    inline bool operator()(const int &a, const int &b) const{
        return w[a] == w[b]? a < b: w[a] < w[b];
    }
};
struct CmpQ{
    inline bool operator()(const int &a, const int &b) const{
        return q[a] == q[b]? a < b: q[a] < q[b];
    }
};
inline bool check(int lim){
    set<int, CmpD> qd;
    set<int, CmpQ> qq;
    set<int, CmpW> ww;
    cost = qs = 0;
    ll c1, c2;
    for(int i = 1; i <= n; ++i){
        if(qd.size() + ww.size() < lim){
            if(qs < k){
                qd.insert(i);
                qq.insert(i);
                cost += q[i];
                ++qs;
            }else{
                c1 = qd.empty()? inf: d[*qd.begin()] + q[i];
                if(w[i] <= c1){
                    ww.insert(i);
                    cost += w[i];
                }else{
                    cost += c1;
                    ww.insert(*qd.begin());
                    qq.erase(*qd.begin());
                    qd.erase(qd.begin());
                    qd.insert(i);
                    qq.insert(i);
                }
            }
        }else{
            c1 = qq.empty()? inf: q[i] - q[*qq.rbegin()];
            c2 = ww.empty()? inf: w[i] - w[*ww.rbegin()];
            if(c1 < 0 && c1 < c2){
                qd.erase(*qq.rbegin());
                qq.erase(*qq.rbegin());
                qd.insert(i);
                qq.insert(i);
                cost += c1;
            }else if(c2 < 0){
                ww.erase(*ww.rbegin());
                ww.insert(i);
                cost += c2;
            }
        }
        if(qd.size() + ww.size() == lim && cost <= S)
            return true;
    }
    return false;
}
int main(){
    cin.tie(0)->sync_with_stdio(false);
    rd(n); rd(k); rd(S);
    if(n != 0){
        for(int i = 1; i <= n; ++i){
            rd(w[i]); rd(q[i]);
            d[i] = w[i] - q[i];
        }
    }else{
        n = 5e4;
        random_device rd;
        mt19937 rnd(rd());
        uniform_int_distribution<> dis(1, 500);
        for(int i = 1; i <= n; ++i){
            q[i] = dis(rnd);
            d[i] = dis(rnd);
            w[i] = q[i] + d[i];
        }
    }
    int lt = 0, rt = n + 1, mid;
    while(lt < rt - 1){
        mid = (lt + rt) >> 1;
        if(check(mid))
            lt = mid;
        else
            rt = mid;
    }
    cout << lt << endl;
    return 0;
}