RT

#include <bits/stdc++.h>
using namespace std;
template < typename T > inline void read(T &x)
{
	x = 0;
	char c = getchar();
	bool flag = false;
	while(c < '0' || c > '9') if(c == '-') flag = true, c = getchar();
	while('0' <= c && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
	if(flag) x = -x;
}
template < typename T > inline void write(T x)
{
	short s[64];
	short top = 0;
	if(x < 0) putchar('-'), x = -x;
	do s[++top] = x % 10, x /= 10; while(x);
	while(top) putchar('0' | s[top--]);
}
void solve();
int main()
{
	solve();
	return 0;
}
#define int long long
struct Chtholly_Tree{
	#define SIT set <node> :: iterator
	struct node{
		int l, r;
		mutable int v;
		bool operator < (const node &a) const {return l < a.l;}
		node(int L, int R, int V): l(L), r(R), v(V){}
		node(int L): l(L){}
	};
	set <node> s;
	void init(int p, int v)
	{
		s.insert(node(p, p, v));
	}
	SIT split(int p)
	{
		SIT it = s.lower_bound(node(p));
		if(it -> l == p && it != s.end()) return it;
		it--;
		int l = it -> l, r = it -> r, v = it -> v;
		s.erase(it);
		s.insert(node(l, p-1, v));
		return s.insert(node(p, r, v)).first;
	}
	void assign(int l, int r, int v)
	{
		SIT it_l, it_r;
		it_r = split(r+1);
		it_l = split(l);
		s.erase(it_l, it_r);
		s.insert(node(l, r, v));
	}
	void add(int l, int r, int v)
	{
		SIT it_l, it_r;
		it_r = split(r+1);
		it_l = split(l);
		for(SIT it=it_l; it!=it_r; it++) it -> v += v;
	}
	int get_max(int l, int r)
	{
		SIT it_l, it_r;
		it_r = split(r+1);
		it_l = split(l);
		int res = -1e18;
		for(SIT it=it_l; it!=it_r; it++) res = max(res, it->v);
		return res;
	}
};
Chtholly_Tree tree;
int n, q;
int opt, l, r, x;
void solve()
{
	read(n), read(q);
	for(int i=1; i<=n; i++){
		read(x);
		tree.init(i, x);
	}
	for(int i=1; i<=q; i++){
		read(opt), read(l), read(r);
		if(opt == 1){
			read(x);
			tree.assign(l, r, x);
		}
		if(opt == 2){
			read(x);
			tree.add(l, r, x);
		}
		if(opt == 3){
			write(tree.get_max(l, r));
			putchar('\n');
		}
	}
}
//珂朵莉树