#include<bits/stdc++.h>
using namespace std;#define ll long long
#define eps 1e-9const int inf = 0x3f3f3f3f;
const int mod = 1e9+7;
const int maxn = 500000 + 8;int n, m, k, x, y;
ll a[maxn];struct node
{int l, r;ll sum, dat, lmax, rmax;
}tree[4 * maxn];void push_down(int i)
{tree[i].sum = tree[i * 2].sum + tree[i * 2 + 1].sum;tree[i].lmax = max(tree[i * 2].lmax, tree[i * 2].sum + tree[i * 2 + 1].lmax);///紧靠左端的最大连续子段和tree[i].rmax = max(tree[i * 2 + 1].rmax, tree[i * 2 + 1].sum + tree[i * 2].rmax);///紧靠右端的最大连续子段和tree[i].dat = max(tree[i * 2].dat, max(tree[i * 2 + 1].dat, tree[i * 2].rmax + tree[i * 2 + 1].lmax));///区间连续最大字段和
}void build(int i, int l, int r)
{tree[i].l = l;tree[i].r = r;if(l == r){tree[i].sum = a[l];tree[i].dat = a[l];tree[i].lmax = a[l];tree[i].rmax = a[l];return;}int mid = (l + r) / 2;build(i * 2, l, mid);build(i * 2 + 1, mid + 1, r);push_down(i);
}void change(int i, int pos, int k)
{if(tree[i].l == tree[i].r){tree[i].sum = k;tree[i].sum = k;tree[i].dat = k;tree[i].lmax = k;tree[i].rmax = k;return;}int mid = (tree[i].l + tree[i].r) / 2;if(pos <= mid)change(i * 2, pos, k);elsechange(i * 2 + 1, pos, k);push_down(i);
}node tmp;node search(int i, int l, int r)
{if(tree[i].l >= l && tree[i].r <= r){return tree[i];}node a, b, c;a.dat = a.lmax = a.rmax = a.sum = -inf;///左儿子b.dat = b.lmax = b.rmax = b.sum = -inf;///右儿子c.dat = c.lmax = c.rmax = -inf;///父节点c.sum = 0;int mid = (tree[i].l + tree[i].r) / 2;if(l <= mid && r <= mid){a = search(i * 2, l, r);c.sum += a.sum;}else if(mid < r && mid < l){b = search(i * 2 + 1, l, r);c.sum += b.sum;}else{a = search(i * 2, l, r);b = search(i * 2 + 1, l, r);c.sum += a.sum + b.sum;}c.dat = max(c.dat, max(a.rmax + b.lmax, max(a.dat, b.dat)));///区间连续最大字段和c.lmax = max(c.lmax, max(a.lmax, a.sum + b.lmax));///紧靠左端的最大连续子段和c.rmax = max(c.rmax, max(b.rmax, b.sum + a.rmax));///紧靠右端的最大连续子段和return c;
}int main()
{std::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);for(int i = 0; i < m; i++){cin>>k>>x>>y;if(k == 1){if(x > y)swap(x, y);cout<<search(1, x, y).dat<<'\n';}else if(k == 2){a[x] = y;change(1, x, y);}}return 0;
}