#include <cstdio>

#include <cctype>

//#define ONLINE_JUDGE

namespace R {

	int x;

	#ifdef ONLINE_JUDGE

	#define M 1 << 27

	char op[M], *ch;

	inline void init() {fread(ch = op, 1, M, stdin);}

	inline int read() {

		while (isspace(*ch)) ch++;

		for (x = *ch & 15, ch++; isdigit(*ch); ch++) x = x * 10 + (*ch & 15);

		return x;

	}

	#else

	char ch;

	inline int read() {

		ch = getchar();

		while (isspace(ch)) ch = getchar();

		for (x = ch & 15, ch = getchar(); isdigit(ch); ch = getchar()) x = x * 10 + (ch & 15);

		return x;

	}

	#endif

}

using R::read;

#define maxn 500010

int n, m;

int s[maxn];

namespace SgT {

	struct node {

		int s, cnt; //s为区间可能众数，cnt这个数比一半区间长度多多少

		inline node(int __s = 0, int __cnt = 0) {s = __s, cnt = __cnt;}

		inline friend node operator + (const node &lhs, const node &rhs) {

			if (lhs.s == rhs.s) return node(lhs.s, lhs.cnt + rhs.cnt);

			if (lhs.cnt > rhs.cnt) return node(lhs.s, lhs.cnt - rhs.cnt);

			else return node(rhs.s, rhs.cnt - lhs.cnt);

		}

	} V[maxn << 2];

	inline void update(int rt) {

		V[rt] = V[rt << 1] + V[rt << 1 | 1];

	}

	void build(int rt, int l, int r) {

		if (l == r) {

			V[rt] = node(s[l], 1);

			return ;

		}

		int mid = l + r >> 1;

		build(rt << 1, l, mid);

		build(rt << 1 | 1, mid + 1, r);

		update(rt);

	}

	int pos, num;

	void __modify(int rt, int l, int r) {

		if (l == r) {

			V[rt] = node(num, 1);

			return ;

		}

		int mid = l + r >> 1;

		if (pos <= mid) __modify(rt << 1, l, mid);

		else __modify(rt << 1 | 1, mid + 1, r);

		update(rt);

	}

	void modify(int __pos, int __num) {

		pos = __pos, num = __num;

		__modify(1, 1, n);

	}

	int L, R;

	node __query(int rt, int l, int r) {

		if (L <= l && R >= r) return V[rt];

		int mid = l + r >> 1;

		node ans;

		if (L <= mid) ans = __query(rt << 1, l, mid);

		if (R > mid) ans = ans + __query(rt << 1 | 1, mid + 1, r);

		return ans;

	}

	int query(int __L, int __R, int tg = 0) {

		L = __L, R = __R;

		return __query(1, 1, n).s;

	}

}

namespace Treap {

	int root[maxn];

	#define N 1000010 + maxn

	int seed = 20040826;

	inline int rand() {return seed *= 48271;}

	int ta, tb, tmp, res;

	int lc[N], rc[N], pri[N], V[N], sz[N], idx;

	inline int nw(int x) {

		pri[++idx] = rand();

		sz[idx] = 1;

		V[idx] = x;

		return idx;

	}

	inline int update(int rt) {

		sz[rt] = sz[lc[rt]] + sz[rc[rt]] + 1;

		return rt;

	}

	void split(int rt, int k, int &x, int &y) {

		if (!rt) x = y = 0;

		else {

			if (V[rt] <= k) split(rc[rt], k, rc[rt], y), x = update(rt);

			else split(lc[rt], k, x, lc[rt]), y = update(rt);

		}

	}

	int merge(int x, int y) {

		if (!x || !y) return x | y;

		if (pri[x] > pri[y]) {rc[x] = merge(rc[x], y); return update(x);}

		else {lc[y] = merge(x, lc[y]); return update(y);}

	}

	void insert(int &rt, int x) {

		if (!rt) rt = nw(x);

		else {

			split(rt, x, ta, tb);

			rt = merge(merge(ta, nw(x)), tb);

		}

	}

	void erase(int &rt, int x) {

		split(rt, x, ta, tb);

		split(ta, x - 1, ta, tmp);

		rt = merge(ta, tb);

	}

	int gtrnk(int &rt, int x) {

		split(rt, x, ta, tb);

		res = sz[ta];

		merge(ta, tb);

		return res;

	}

	int query(int &rt, int l, int r) {

//		printf("%d %d\n", gtrnk(rt, r), gtrnk(rt, l));

		return gtrnk(rt, r) - gtrnk(rt, l - 1);

	}

	void modify(int tg, int &before, int after) {

		erase(root[before], tg);

		insert(root[after], tg);

		before = after;

	}

	#undef N

}

using Treap::root;

int main() {

	#ifdef ONLINE_JUDGE

	R::init();

	#endif

	n = read(), m = read();

	for (int i = 1; i <= n; i++) Treap::insert(root[s[i] = read()], i);

	SgT::build(1, 1, n);

	while (m --> 0) {

		int l = read(), r = read(), s = read(), k = read();

		int tmp = SgT::query(l, r);

		int CNT = Treap::query(root[tmp], l, r);

		if (CNT <= (r - l + 1 >> 1)) tmp = s;

		printf("%d\n", tmp);

		for (int i = 0, x; i < k; i++) {

			x = read();

			SgT::modify(x, tmp);

			Treap::modify(x, ::s[x], tmp);

		}

	}

	int tmp = SgT::query(1, n);

	int CNT = Treap::query(root[tmp], 1, n);

	if (CNT <= n >> 1) tmp = -1;

	printf("%d\n", tmp);

	return 0;

}