#include <bits/stdc++.h>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<long long> v(n);
    for(int i = 0; i < n; i++) {
        string s;
        cin >> s >> v[i];
    }
    sort(v.begin(), v.end());
    long long l = v[0], r = v.back(), mid;
    long long f;
    cin >> f;
    while(l <= r) {
        mid = (l + r) / 2;
        long long need = 0;
        for(int i = 0; i < n; i++) {
            need += (v[i] - mid > 0 ? v[i] - mid : 0);
        }
        //cout << l << " " << mid << " " << r << "\n";
        if(need > f) {
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }
    cout << l << "\n";
    return 0;
}