#pragma GCC optimize(3)
#include <iostream>
#include <algorithm>
using namespace std;
const int N = 500010;
int n, m;
int a[N];

struct T{
    int l, r;
    int sum, premax, sufmax, tmax;
}tr[N * 4];

inline void pushup(int u) {
    tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
    tr[u].premax = max(tr[u << 1].premax, tr[u << 1].sum + tr[u << 1 | 1].premax);
    tr[u].sufmax = max(tr[u << 1 | 1].sufmax, tr[u << 1 | 1].sum + tr[u << 1].sufmax);
    tr[u].tmax = max({tr[u << 1].sufmax + tr[u << 1 | 1].premax, tr[u << 1].tmax, tr[u << 1 | 1].tmax});
}

void build(int u, int l, int r) {
    tr[u] = {l, r, a[l], a[l], a[l], a[l]};
    if(l == r) return;
    int mid = tr[u].l + tr[u].r >> 1;
    build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
    pushup(u);
}

void modify(int u, int k, int v) {
    if(tr[u].l == tr[u].r) {
        tr[u] = {k, k, v, v, v, v};
        return;
    }
    int mid = tr[u].l + tr[u].r >> 1;
    if(k <= mid) modify(u << 1, k, v);
    else modify(u << 1 | 1, k, v);
    pushup(u);
}

T query(int u, int l, int r) {
    if(l <= tr[u].l && tr[u].r <= r) return tr[u];
    int mid = tr[u].l + tr[u].r >> 1;
    if(r <= mid) return query(u << 1, l, r); 
    if(l > mid) return query(u << 1 | 1, l, r);
    T lson = query(u << 1, l, r);
    T rson = query(u << 1 | 1, l, r);
    T ans;
    ans.sum = lson.sum + rson.sum;
    ans.premax = max(lson.premax, lson.sum + rson.premax);
    ans.sufmax = max(rson.sufmax, rson.sum + lson.sufmax);
    ans.tmax = max({lson.tmax, rson.tmax, lson.sufmax + rson.premax});
    return ans;
}

int main() {
    scanf("%d%d", &n, &m);
    for(int i = 1; i <= n; i++) scanf("%d", &a[i]);
    build(1, 1, n);
    while(m--) {
        int t, x ,y;
        scanf("%d%d%d", &t, &x, &y);
        if(t == 1) {
            if (x > y) swap(x, y);
            printf("%d\n", query(1, x, y).tmax); 
        }
        else modify(1, x, y);
    }
    return 0;
}