#include <cstdio>
#include <algorithm>

FILE *fin, *fout;

#define MAXN 100000

int N, M, A[MAXN + 1];
int arb[MAXN * 3 + 1];

void build(int nod, int st, int dr) {
	if (st > dr)
		return;
	if (st == dr) {
		arb[nod] = A[st];
		return;
	}//frunza
	build(2 * nod, st, (st + dr) / 2);
	build(2 * nod + 1, (st + dr) / 2 + 1, dr);
	arb[nod] = std::max(arb[nod * 2], arb[nod * 2 + 1]);
}

int val, l1, r1;
int lazy[MAXN * 3 + 1];

void update(int nod, int st, int dr) {
	if (st > dr)
		return;
	if (st > r1 || dr < l1)//in afara intervalului
		return;
	if (lazy[nod] != 0) {//bag update
		arb[nod] = lazy[nod];
		if (st != dr) {// nu e frunza
			lazy[nod * 2] = lazy[nod];
			lazy[nod * 2 + 1] = lazy[nod];
		}
		lazy[nod] = 0;
	}
	if (l1 <= st && dr <= r1) {
		arb[nod] = val;
		if (st != dr) {
			lazy[nod * 2] = val;//marchez ca va trebui candva sa le updatez
			lazy[nod * 2 + 1] = val;
		}
		return;
	}
	update(nod * 2, st, (st + dr) / 2);
	update(nod * 2 + 1, (st + dr) / 2 + 1, dr);
	arb[nod] = std::max(arb[nod * 2], arb[nod * 2 + 1]);
}

int max;

void query(int nod, int st, int dr) {
	if (st > dr)
		return;
	if (dr < l1 || st > r1)//daca nu se afla in interval, nu are rost sa ma complic
		return;
	if (lazy[nod] != 0) {
		arb[nod] = lazy[nod];
		if (st != dr) {
			lazy[nod * 2] = lazy[nod];
			lazy[nod * 2 + 1] = lazy[nod];
		}
		lazy[nod] = 0;
	}
	if (l1 <= st && dr <= r1) {
		max = std::max(max, arb[nod]);
		return;
	}
	query(nod * 2, st, (st + dr) / 2);
	query(nod * 2 + 1, (st + dr) / 2 + 1, dr);
}

int main() {
	fin = fopen("arbint.in", "r");
	fout = fopen("arbint.out", "w");
	fscanf(fin, "%d%d", &N, &M);
	for (int i = 1; i <= N; i++)
		fscanf(fin, "%d", &A[i]);
	build(1, 1, N);
	for (int i = 1; i <= M; i++) {
		int p, a, b, c;
		fscanf(fin, "%d%d%d", &p, &a, &b);
		if (p == 1) {
			fscanf(fin, "%d", &c);
			val = b, l1 = a, r1 = c;
			update(1, 1, N);
		}
		else {
			l1 = a, r1 = b;
			max = -1;
			query(1, 1, N);
			fprintf(fout, "%d\n", max);
		}
	}
	fclose(fin);
	fclose(fout);
	return 0;
}