#include <bits/stdc++.h>

using namespace std;
ifstream f("aib.in");
ofstream g("aib.out");
const int N = 10010;
int n,m,aib[N];
int suma(int i)
{
    int rez=0;
    for(; i; i-=i&(-i))
        rez+=aib[i];
    return rez;
}
void adun(int i,int val)
{
    for(; i<=n; i+=i&(-i))
        aib[i]+=val;
}
int main()
{
    f>>n>>m;
    for(int i=1; i<=n; i++)
    {
        int x;
        f>>x;
        adun(i,x);
    }
    for(; m; m--)
    {
        int tip;
        f>>tip;
        if(tip==0)
        {
            int i,x;
            f>>i>>x;
            adun(i,x);
        }
        else if(tip==1)
        {
            int st,dr;
            f>>st>>dr;
            g<<suma(dr)-suma(st-1)<<'\n';
        }
        else
        {
            int lo,hi,mi,val;
            f>>val;
            lo=0;hi=n;
            while(hi-lo>1)
            {
                mi=(lo+hi)/2;
                if(suma(mi)<val)
                    lo=mi;
                else
                    hi=mi;
            }
            if(suma(hi)!=val)
                hi=-1;
            g<<hi<<'\n';
        }
    }
    return 0;
}

//1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
//x   x   x   x   x     x     x     x     x     x     x     x
//x x     x x     x  x        x  x        x  x        x  x
//x x x x         x  x  x  x              x  x  x  x
//x x x x x x x x
//x x x x x x x x x  x  x  x  x  x  x  x
//
//1110 ->14 4k*2 ( tai 2)
//1100 ->12 8k+4 (tai 4)
//1000 ->8
//0000 ->0
//21 1+20 10101
//20 4+16 10100
//16 16   10000
//0       00000
//
//celMaiMicBit(x) = x&(-x); /// !!!!!!!!!!!
//1010  10
//  10
// 1100 12
//  100
// 10000 16
// 10000
//100000 32>23