inline int lowbit(int x)
{return x&(-x);
}

inline void add(int x,int y) //给x加上y
{while(x <= n){c[x] += y;x += lowbit(x);}return ;
}inline int query(int x) //查询1~7的前缀和
{int ans = 0;while(x){ans += c[x];x -= lowbit(x);}return ans;
}

#include <cstdio>
#include <cstring>
#include <algorithm>const int maxn = 1e6 + 6;
int n,m;
int cost[maxn];inline int read()
{char ch = getchar();int x = 0,f = 1;while(ch<'0'||ch>'9'){if(ch == '-') f = -1; ch = getchar();}while(ch>='0'&&ch<='9'){x = x*10 + ch -'0'; ch = getchar();}return x*f;
}inline int lb(int  x)
{return x&(-x);
}inline void add(int a,int v)
{while(a<=n){cost[a] += v;a += lb(a);}
}inline int query(int a)
{int ans = 0;while(a){ans += cost[a];a -= lb(a);}return ans;
}int main(int argc, char const *argv[])
{n = read();m = read();int pre = 0;for(int i = 1;i <= n;i ++){int val = read();add(i,val - pre);pre = val;}for(int i = 1;i <= m;i ++){int flag,x,y,k;flag = read();if(flag == 1){x = read();y = read();k = read();add(x,k);add(y+1,-k);}else{x = read();printf("%d\n",query(x));}}return 0;
}

inline void modify(int x,int y) //把x的值改为y
{a[x] = y;while(x <= n){c[x] = a[x];for(int i = 1;i < lowbit(x);i <<= 1) c[x] = std::max(c[x],c[x - i]);x += lowbit(x);}return ;
}

inline int query(int l,int y) //查询区间l ~ r的最大值
{int ans = 0;while(l <= r){ans = std::max(ans,a[r]);r--;while(l <= r - lowbit(r)){ans = std::max(ans,c[r]);r -= lowbit(r);}}return ans;
}

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>const int maxn = 2e5+5;
int n,m;
int a[maxn];
int cost[maxn];inline int lb(int x)
{return x&(-x);
}inline void modify(int x)
{while(x<=n){cost[x] = a[x];for(int i = 1;i < lb(x);i<<=1) cost[x] = std::max(cost[x],cost[x-i]);x += lb(x);}
}inline int query(int l,int r)
{int ans = 0;while(l <= r){ans = std::max(ans,a[r]);r --;while(l <= r-lb(r)) {ans = std::max(ans,cost[r]);r -= lb(r);}}return ans;
}int main()
{while(scanf("%d %d",&n,&m)!=EOF){memset(a,0,sizeof(a));memset(cost,0,sizeof(cost));for(int i = 1;i <= n;i ++){scanf("%d",&a[i]);modify(i);}for(int i = 1;i <= m;i ++){char flag = getchar();while(flag!='Q'&&flag!='U')flag = getchar();if(flag=='Q'){int l,r;scanf("%d %d",&l,&r);printf("%d\n",query(l,r));}else if(flag=='U'){int x,v;scanf("%d %d",&x,&v);a[x] = v;modify(x);}}}return 0;
}