#include <fstream>

using namespace std;

ifstream f("aib.in");
ofstream g("aib.out");

int n, m, i, j;
int tip, x, suma;
int poz, val;
int ST, DR;
int a, b, mij, k;
int s[262144];

void update(int nod, int st, int dr)
{
    if (st == dr)
    {
        s[nod] += val;
        return;
    }

    int mij = (st + dr) / 2;
    if (poz <= mij)
        update(nod*2, st, mij);
    else
        update(nod*2+1, mij+1, dr);

    s[nod] = s[nod*2] + s[nod*2+1];
}

void query(int nod, int st, int dr)
{
    if (ST <= st  &&  dr <= DR)
    {
        suma += s[nod];
        return;
    }

    int mij = (st + dr) / 2;
    if (mij >= ST)
        query(nod*2, st, mij);
    if (mij < DR)
        query(nod*2+1, mij+1, dr);
}

int main()
{
    f >> n >> m;

    for (i=1; i<=n; i++)
    {
        f >> x;
        poz = i,  val = x;
        update(1, 1, n);
    }

    for (i=1; i<=m; i++)
    {
        f >> tip;
        if (tip == 0)
        {
            f >> a >> b;
            poz = a,  val = b;
            update(1, 1, n);
        }
        else if (tip == 1)
        {
            f >> a >> b;

            suma = 0;
            ST = a,  DR = b;

            query(1, 1, n);
            g << suma << "\n";
        }
        else
        {
            f >> val;
            a = 1, b = n, k = -1;
            while (a <= b)
            {
                mij = (a + b) / 2;

                ST = 1,  DR = mij;
                suma = 0;

                query(1, 1, n);

                if (suma == val)
                {
                    k = mij;
                    b = mij - 1;
                }
                else if (suma < val)
                    a = mij + 1;
                else
                    b = mij - 1;
            }

             g << k << "\n";
        }
    }

    return 0;
}