#include <iostream>
#include <vector>
#include <unordered_map>

using namespace std;

int findMinFreqInteger(const vector<int>& A, int l, int r) {
    unordered_map<int, int> freq;
    int min_freq = (r - l + 1) / 3 + 1;
    int min_integer = -1;

    for (int i = l; i <= r; ++i) {
        freq[A[i]]++;
        if (freq[A[i]] >= min_freq && (min_integer == -1 || A[i] < min_integer)) {
            min_integer = A[i];
        }
    }

    return min_integer;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int N, Q;
    cin >> N >> Q;

    vector<int> A(N);
    for (int i = 0; i < N; ++i) {
        cin >> A[i];
    }

    for (int i = 0; i < Q; ++i) {
        int l, r;
        cin >> l >> r;
        l--;
        r--;

        int min_integer = findMinFreqInteger(A, l, r);
        cout << min_integer << endl;
    }

    return 0;
}