#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;

int m, q;

int klu[1000000], ost[1000000], pre[1000000], sor[1000000], odp[1000000], roz, mx, ret;
vector<pair<int, int> > pyt[1000000];

int main() {
	while (1) {
		scanf("%d%d", &m, &q);
		mx = -1;
		if (!m && !q)
			return 0;
		for (int i = 0; i < m; ++i) {
			scanf("%d", klu + i);
			sor[i] = klu[i];
		}
		sort(sor, sor + m);
		roz = unique(sor, sor + m) - sor;
		fill(ost, ost + roz, -1);
		for (int i = 0; i < roz; ++i)
			pre[i] = sor[i];
		for (int i = 0; i < q; ++i) {
			int odk, dok;
			scanf("%d%d", &odk, &dok);
			pyt[dok - 1].push_back(make_pair(odk - 1, i));
		}
		for (int i = 0; i < m; ++i) {
			int ak = lower_bound(sor, sor + roz, klu[i]) - sor;
			if (mx < ost[ak]) {
				mx = ost[ak];
				ret = ak;
			}
			ost[ak] = i;
			for (vector<pair<int, int> >::iterator it = pyt[i].begin(); it != pyt[i].end(); ++it)
				if (it->first <= mx)
					odp[it->second] = ret;
				else
					odp[it->second] = -1;
		}
		for (int i = 0; i < q; ++i)
			if (odp[i] == -1)
				printf("OK\n");
			else
				printf("%d\n", pre[odp[i]]);
		printf("\n");
		for (int i = 0; i < m; ++i)
			pyt[i].clear();
		
	}
}