#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ls (p << 1) 
#define rs (ls | 1)
#define len(p) (t[p].r - t[p].l + 1)

const int N = 5e5 + 5;

int n, m, a[N];

struct Info{
	int l, r, sum, lmx, rmx, ans;
	
} t[N << 2];
Info operator + (const Info &lhs, const Info &rhs) {
	Info res;
	res.ans = max(max(lhs.ans, rhs.ans), lhs.rmx + rhs.lmx);
	res.lmx = max(lhs.lmx, lhs.sum + rhs.lmx);
	res.rmx = max(rhs.rmx, rhs.sum + lhs.rmx);
	res.sum = lhs.sum + rhs.sum;
	return res;
}
void pushup(int p) {
	t[p] = t[ls] + t[rs];
//	cout << p << " "<<endl;
}

void build(int p, int l, int r) {
	t[p].l = l, t[p].r = r;
//	cout << p << ' ' << t[p].l << ' '<< t[p].r << endl;
	if (l == r) {
		t[p].sum = t[p].lmx = t[p].rmx = t[p].ans = a[l];
		return;
	}
	int mid = (l + r) >> 1;
	build(ls, l, mid);
	build(rs, mid + 1, r);
	pushup(p);
}

void change(int p, int pos, int x) {
	if (t[p].l == t[p].r) {
		t[p].sum = t[p].lmx = t[p].rmx = t[p].ans = x;
		return;
	}
	int mid = (t[p].l + t[p].r) >> 1;
	if (mid >= pos) change(ls, pos, x);
	if (mid < pos) change(rs, pos ,x);
	pushup(p);
}

Info query(int p, int l, int r) {
	if (t[p].l >= l && t[p].r <= r) return t[p];
	int mid = (t[p].l + t[p].r) >> 1;
	if (mid >= l && mid < r) return query(ls, l, r) + query(rs, l, r);
	if (l <= mid) return query(ls, l, r);
	return query(rs, l, r);
}
signed main() {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	build(1, 1, n);
	while (m--) {
		int k;
		cin >> k;
		if (k == 1) {
			int l, r;
			cin >> l >> r;
			cout << query(1, min(l, r), max(l, r)).ans << endl;
		} else {
			int p, x;
			cin >> p >> x;
			change(1, p, x);
		}
	}
	return 0;
}