#include <fstream>
#include<cmath>
using namespace std;
int bat[318], v[100005];
int main()
{
    ifstream cin("batog.in");
    ofstream cout("batog.out");
    int n, i, k=0,l, sum=0, cnt=-1, poz, val, m, j, st, dr;
    char ch;
    cin>>n>>m;
    l=sqrt(n);
    for (i=0;i<n;i++)
    {
        cin>>v[i];
        if (i%l==0)
          cnt++;
        bat[cnt]+=v[i];
    }


    for (i=1;i<=m;i++)
    {
        cin>>ch>>poz>>val;
        sum=0;
        poz--;
        if(ch=='U')
        {
            bat[poz/l]+=val-v[poz];
            v[poz]=val;
        }
        else
        {
            st=poz;
            dr=val-1;
            while( st<=dr && st%l!=0)
            {
                sum+=v[st++];
            }
            while(st<=dr && st+l-1<=dr)
            {
                sum+=bat[st/l];
                st+=l;
            }
            while(st<=dr)
            {
                sum+=v[st++];
            }
            cout<<sum<<'\n';
        }
    }
    return 0;
}