#include <iostream>
#include <vector>
#include <algorithm>

using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::string;
using std::swap;
using std::pair;
using std::min;
using std::max;
using pii = pair<int, int>;


pii merge(const pii& l, const pii& r, const vector<int> &a) {
    pii ret = {-1, -1};
    vector<int> inds = {l.first, l.second, r.first, r.second};
    vector<pii> elements;
    for (auto i : inds) {
        if (i != -1) {
            bool in = false;
            for (auto el : elements) {
                if (el.first == a[i] && el.second == i) {
                    in = true;
                    break;
                }
            }
            if (!in) {
                elements.push_back((pii){a[i], i});
            }
        }
    }
    std::sort(elements.begin(), elements.end());
    ret.first = elements[0].second;
    if (elements.size() >= 2) {
        ret.second = elements[1].second;
    }
    return ret;
}


int main() {
    std::ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m;
    cin >> n >> m;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) cin >> a[i];
    vector<int> pow;
    for (int p = 1; p <= n; p <<= 1) {
        pow.push_back(p);
    }
    vector<int> find_p(n + 1);
    int deg = 0;
    for (int i = 1; i <= n; ++i) {
        if (pow[deg] * 2 <= i) {
            ++deg;
        }
        find_p[i] = deg;
    }
    vector<vector<pii> > sparse_table(pow.size());
    for (int p = 0; p < pow.size(); ++p) {
        for (int i = 0; i + pow[p] <= n; ++i) {
            if (p == 0) {
                sparse_table[p].push_back({i, -1});
            } else {
                pii left = sparse_table[p - 1][i];
                pii right = sparse_table[p - 1][i + pow[p - 1]];
                sparse_table[p].push_back(merge(left, right, a));
            }
        }
    }
    while (m--) {
        int l, r;
        cin >> l >> r;
        l--;
        int p = find_p[r - l];
        pii left = sparse_table[p][l];
        pii right = sparse_table[p][r - pow[p]];
        int res = merge(left, right, a).second;
        if (res == -1) {
            cout << res << '\n';
        } else {
            cout << a[res] << '\n';
        }
    }
}