#include <iostream>
#define int long long
using namespace std;
const int inf = 9223372036854775807;
const int maxn = 1000005;
int n, q;
int a[maxn];
int w[maxn * 4];
int lzy_1[maxn * 4];
int lzy_2[maxn * 4];
bool ir (int l, int r, int L, int R) {
	return (L <= l and r <= R);
}
bool otr (int l, int r, int L, int R) {
	return (l > R or r < L);
}
void pushup (const int u) {
	w[u] = max (w[u * 2], w[u * 2 + 1]);
	return;
}
void maketag (const int u, int x, bool type) {
	if (not type) {
		if (lzy_2[u] == inf) lzy_1[u] += x;
		else lzy_2[u] += x;
		w[u] += x;
	} else {
		lzy_1[u] = 0;
		lzy_2[u] = x;
		w[u] = x;
	}
}
void pushdown (const int u) {
	if (lzy_2[u] == inf) {
		maketag (u * 2, lzy_1[u], 0);
		maketag (u * 2 + 1, lzy_1[u], 0);
		lzy_1[u] = 0;
	} else {
		maketag (u * 2, lzy_2[u], 1);
		maketag (u * 2 + 1, lzy_2[u], 1);
		lzy_2[u] = inf;
	}
}
void build (const int u, int l, int r) {
	lzy_2[u] = inf;
	if (l == r) {
		w[u] = a[l];
		return;
	}
	int m = (l + r) >> 1;
	build (u * 2, l, m);
	build (u * 2 + 1, m + 1, r);
	pushup (u);
	return;
}
int query (int l, int r, int L, int R, const int u) {
	if (ir (L, R, l, r)) {
		return w[u];
	} else if (not otr (L, R, l, r)) {
		int m = (L + R) >> 1;
		pushdown (u);
		return max (query (l, r, L, m, u * 2), query (l, r, m + 1, R, u * 2 + 1));
	} else {
		return 0;
	}
}
void update (int l, int r, int L, int R, const int u, int x, bool type) {
	if (ir (L, R, l, r)) {
		maketag (u, x, type);
		return;
	} else if (not otr (L, R, l, r)) {
		int m = (L + R) >> 1;
		pushdown (u);
		update (l, r, L, m, u * 2, x, type);
		update (l, r, m + 1, R, u * 2 + 1, x, type);
		pushup (u);
	} else {
		return;
	}
}
int op, l, r, x;
signed main () {
	ios::sync_with_stdio (false);
	cin.tie (0);
	cout.tie (0);
	cin >> n >> q;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	build (1, 1, n);
	while (q--) {
		cin >> op;
		if (op == 1) {
			cin >> l >> r >> x;
			update (l, r, 1, n, 1, x, 1);
		} else if (op == 2) {
			cin >> l >> r >> x;
			update (l, r, 1, n, 1, x, 0);
		} else {
			cin >> l >> r;
			cout << query (l, r, 1, n, 1) << '\n';
		}
	}
	return 0;
}