#include <bits/stdc++.h>
using namespace std;
const int maxn=505000;
int val[maxn<<2] ;
struct Node{int left,right,maxv,sum;
}tree[maxn<<2];
void update(int o,int l,int r){tree[o].sum=tree[o<<1].sum+tree[o<<1|1].sum;tree[o].left=max(tree[o<<1].left,tree[o<<1].sum+tree[o<<1|1].left);tree[o].right=max(tree[o<<1|1].right,tree[o<<1|1].sum+tree[o<<1].right);tree[o].maxv=max(tree[o<<1].right+tree[o<<1|1].left,max(tree[o<<1].maxv,tree[o<<1|1].maxv));
}
void build(int o,int l,int r){if(l==r){tree[o].sum=tree[o].left=tree[o].right=tree[o].maxv=val[l];return;}int mid=l+r>>1;build(o<<1,l,mid); build(o<<1|1,mid+1,r);update(o,l,r);
}
void modify(int o,int l,int r,int v,int L){if(l>L||r<L) return;if(l==r){ tree[o].sum=tree[o].left=tree[o].right=tree[o].maxv=v; return;}int mid=l+r>>1;modify(o<<1,l,mid,v,L); modify(o<<1|1,mid+1,r,v,L);update(o,l,r);
}
Node query(int o,int l,int r,int L,int R){if(L<=l&&R>=r) return tree[o]; int mid=l+r>>1;if(R<=mid) return query(o<<1,l,mid,L,R);else if(L>mid) return query(o<<1|1,mid+1,r,L,R);else{Node res1=query(o<<1,l,mid,L,R),res2=query(o<<1|1,mid+1,r,L,R);Node res;res.sum=res1.sum+res2.sum;res.left=max(res1.left,res1.sum+res2.left);res.right=max(res2.right,res2.sum+res1.right);res.maxv=max(res1.right+res2.left,max(res1.maxv,res2.maxv));return res;}
}int main(){int n,m;scanf("%d%d",&n,&m);for(int i=1;i<=n;i++) scanf("%d",&val[i]);build(1,1,n);int k,a,b;while(m--){scanf("%d%d%d",&k,&a,&b);if(k==1){if(a>b) swap(a,b); printf("%d\n",query(1,1,n,a,b).maxv);}else modify(1,1,n,b,a);}
}