#include<cstdio>
#include<iostream>
#include<string>
#include<cstring>
#include<queue>
#include<vector>
#include<stack>
#include<vector>
#include<map>
#include<set>
#include<algorithm>
//#include<bits/stdc++.h>
using namespace std;#define PB push_back
#define MP make_pair
#define fi first
#define se second
#define PS pushconst int maxn = 1e5+5;
const int maxsz = 1e4+5;
struct BinaryHEAP
{int Heap[maxsz];int sz;#define Cmp(a,b) ((a)>(b))void push(int x){int i = ++sz;while(i > 1){int p = i>>1;if(!Cmp(x,Heap[p])) break;Heap[i] = Heap[p];i = p;}Heap[i] = x;}void pop(){int x = Heap[sz--];int i = 1;while((i<<1)<=sz){int a = i<<1, b = i<<1|1;if(b<=sz && Cmp(Heap[b],Heap[a])) a = b;if(!Cmp(Heap[a],x)) break;Heap[i] = Heap[a];i = a;}Heap[i] = x;}int top(){ return Heap[1]; }//int operator[](int x){ return Heap[x]; }
}q;pair<int,int> cow[maxn];
int N, C, F;
int Half;
int preSum[maxn];int sol()
{sort(cow,cow+C);int Half = N>>1, sum = 0;for(int i = 0; i < Half; i++) {sum += cow[i].se;q.push(cow[i].se);}for(int i = Half; i < C-Half; i++){preSum[i] = sum;if(q.top() > cow[i].se) {sum -= q.top();q.pop();sum += cow[i].se;q.push(cow[i].se);}}q.sz = 0;sum = 0;for(int i = C-Half; i < C; i++) {sum += cow[i].se;q.push(cow[i].se);}for(int i = C-Half; --i >= Half; ){if(sum + preSum[i] + cow[i].se <= F) return cow[i].fi;if(q.top() > cow[i].se) {sum -= q.top();q.pop();sum += cow[i].se;q.push(cow[i].se);}}return -1;
}//#define LOCAL
int main()
{
#ifdef LOCALfreopen("in.txt","r",stdin);
#endifscanf("%d%d%d",&N,&C,&F);for(int i = 0; i < C; i++){scanf("%d%d",&cow[i].fi,&cow[i].se);}printf("%d\n",sol());return 0;
}