#include <stdio.h>
#include <memory.h>
#include <malloc.h>
#include <stdlib.h>
#define size (10000000)
#define hash(x) (((x)*0x12345u)%(size))
#define uint unsigned int

/*struct ww {
	int key;
	int pos;
}*/

int main() {
	uint *set = (uint*)malloc( size * sizeof( uint ) );
	uint *key = (uint*)malloc( 1000001 * sizeof( uint ) );
	uint *end = set;
	end += size - 1;
	if( !set || !key ) {
		printf("mem");
		return 1;
	};
	for( ;; ) {
		uint ks, qs, f, t;
		scanf( "%u %u", &ks, &qs );
		if( !ks && !qs ) return 0;
		for( uint i = 0; i < ks; i++ ) {
			scanf( "%u", key + i );
		}
		for( uint j = 0; j < qs; j++ ) {
			memset( set, 0, size * sizeof( uint ) );
			scanf( "%u %u", &f, &t );
			t--;
			for( uint i = f - 1; i <= t; i++ ) {
				uint n = key[i];
				uint *k = set + hash( n );
				if( k == set ) printf( "az: %d %d", n, hash( n ) );
				uint *start = k;
				while( *k ) {
					if( *k == n ) {
						printf( "%d\n", n );
						goto skip;
					}
					k++;
					if( k == start ) return 1;
					if( k > end ) k = set;
				}
				*k = n;
			}
			printf("OK\n");
			skip: ;
		}
		printf("\n");
	}
}