6

#include <bits/stdc++.h>
using namespace std;

const int N = 2e5 + 10;
int n, s;
int S;
int ql[N], qr[N];
vector <pair <int, int>> lr;


bool ok(int c){
    int cntBigR = 0;
    int cntBigL = 0;
    for (int i = 1; i <= n; i++){
        if (qr[i] >= c){
            cntBigR++;
        }
        if (ql[i] > c){
            cntBigL++;
        }
    }
    if (cntBigR < (n + 1) / 2) return false;
    assert(cntBigL < (n + 1) / 2);
    long long sum = 0;
    int needL = (n + 1);
    int need = needL / 2;
    for (int i = n - 1; i >= 0; i--){
      if (need == 0) break;
        if (lr[i].second < c) continue;
        need--;
        if (lr[i].first <= c) sum += c - lr[i].first;
    }
    return sum <= s;
}

void solve(){
    cin >> n >> s;
    for (int i = 1; i <= n; i++){
        cin >> ql[i] >> qr[i];
    }
    for (int i = 1; i <= n; i++){
        s -= ql[i];
        lr.push_back({ql[i], qr[i]});
    }
    sort(lr.begin(), lr.end());
    assert(s >= 0);
    sort(ql + 1, ql + n + 1);
    sort(qr + 1, qr + n + 1);
    int l = ql[(n + 1) / 2];
    int r = 1e9 + 10;
    int ans = 0;
    while (l <= r){
        int mid = (l + r) >> 1;
        if (ok(mid)){
            l = mid + 1;
            ans = mid;
        }else{
            r = mid - 1;
        }
    }
    cout << ans << endl;
}

int main(){

    ios::sync_with_stdio(NULL), cin.tie(0), cout.tie(0);
    solve();
}