#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> a;
    int c;
    //获取初值
    for (int i = 0; i < n; i++) {
        cin >> c;
        a.push_back(c);
    }

    bool found = false;
    for (int i = 0; i < n - 1; i++) {
        int xiao = 0;
        int da = 0;
        for (int j = i + 1; j < n; j++) {
            if (a[j] > a[i])da++;
            if (a[j] < a[i]) xiao++;
        }
        if (xiao == da) {
            cout << a[i] << endl;
            found = true;
            break;
        }
    }
    if (!found) cout << "-1" << endl;
    return 0;
}