#include <bits/stdc++.h>

 using namespace std;

 typedef long long ll;

 typedef unsigned long long ull;

 #define INF 0X3f3f3f3f

 const ll MAXN = 2e5 + ;

 const ll MOD = 1e9 + ;

 ll a[MAXN];

 struct node

 {

     int left, right; //区间端点

     ll max, sum;     //看题目要求

     ll lazy;

     void update(ll x)

     {

         sum += (right - left + ) * x;

         lazy += x;

     }

 } tree[MAXN << ];

 //建树，开四倍

 void push_up(int x)

 {

     tree[x].sum = tree[x << ].sum + tree[x <<  | ].sum;

     tree[x].max = max(tree[x << ].max, tree[x <<  | ].max);

 }

 void push_down(int x)

 {

     ll lazeval = tree[x].lazy;

     if (lazeval)

     {

         tree[x << ].update(lazeval);

         tree[x <<  | ].update(lazeval);

         tree[x].lazy = ;

     }

 }

 //若原数组从a[1]~a[n]，调用build(1,1,n);

 void build(int x, int l, int r)

 {

     tree[x].left = l;

     tree[x].right = r;

     tree[x].sum = tree[x].lazy = ;

     if (l == r) //若到达叶节点

     {

         tree[x].sum = a[l]; //存储A数组的值

         tree[x].max = a[l];

     }

     else

     {

         int mid = (l + r) / ;

         build(x << , l, mid);

         build(x <<  | , mid + , r);

         push_up(x);

     }

     return;

 }

 //update(1,l,r,v)

 void update(int x, int l, int r, ll v) //区间更新

 {

     int L = tree[x].left, R = tree[x].right;

     if (l <= L && R <= r)

     {

         tree[x].update(v);

         tree[x].max += v;

     }

     else

     {

         push_down(x);

         int mid = (L + R) / ;

         if (mid >= l)

             update(x << , l, r, v);

         if (r > mid)

             update(x <<  | , l, r, v);

         push_up(x);

     }

 }

 //单点更新,更新pos点，调用add(1,pos,v)

 void add(int x, int pos, ll v) //当前更新的节点的编号为id（一般是以1为第一个编号）。pos为需要更新的点的位置，v为修改的值的大小

 {

     int L = tree[x].left, R = tree[x].right;

     if (L == pos && R == pos) //左右端点均和pos相等，说明找到了pos所在的叶子节点

     {

         tree[x].sum += v;

         tree[x].max += v;

         return; //找到了叶子节点就不需要在向下寻找了

     }

     int mid = (L + R) / ;

     if (pos <= mid)

         add(x << , pos, v);

     else

         add(x <<  | , pos, v); //寻找k所在的子区间

     push_up(x);                  //向上更新

 }

 //调用query_sum（1,l,r)即可查询[l,r]区间内元素的总和

 //区间查询

 ll query_sum(int x, int l, int r)

 {

     int L = tree[x].left, R = tree[x].right;

     if (l <= L && R <= r)

         return tree[x].sum;

     else

     {

         push_down(x);

         ll ans = ;

         int mid = (L + R) / ;

         if (mid >= l)

             ans += query_sum(x << , l, r);

         if (r > mid)

             ans += query_sum(x <<  | , l, r);

         push_up(x);

         return ans;

     }

 }

 //调用query_max(1,l,r)即可求[l,r]区间内元素的最大值

 ll query_max(int x, int l, int r)

 {

     int L = tree[x].left, R = tree[x].right;

     if (l == L && R == r)

         return tree[x].max;

     else

     {

         push_down(x);

         int mid = (L + R) / ;

         if (r <= mid)

             return query_max(x << , l, r);

         else if (l > mid)

             return query_max(x <<  | , l, r);

         else

             return max(query_max(x << , l, mid), query_max(x <<  | , mid+, r));

     }

 }

 int main()

 {

     ll n, m;

     while (scanf("%lld%lld", &n, &m) != EOF)

     {

         for (int i = ; i <= n; i++)

             scanf("%lld", &a[i]);

         build(, , n);

         getchar();

         while (m--)

         {

             int l, r;

             char que;

             scanf("%c %d %d", &que, &l, &r);

             getchar();

             if (que == 'Q')

                 printf("%lld\n", query_max(, l, r));

             else if (que == 'U')

                 update(, l,l, r - a[l]),a[l]=r;

         }

     }

     return ;

 }