#include<cstdio>
#define aib_SIZE 100000
using namespace std;

int aib[aib_SIZE+1], n, m;

inline void updateAIB(int pos, int x) {
    do {
        aib[pos] += x;
        pos += pos & (-pos);
    }while(pos <= n);
}

inline int sum(int x) {
    int suma = 0;
    while(x) {
        suma += aib[x];
        x &= (x-1);
    }
    return suma;
}

int binarySearch(int x) {
    int left, right, mid, pos, suma;
    left = 1;
    right = n;
    pos = -1;
    while(left <= right && pos == -1) {
        mid = (left + right) >> 1;
        suma = sum(mid);
        if(x == suma)
            pos = mid;
        else if(x < suma)
            right = mid - 1;
        else left = mid + 1;
    }
    return pos;
}

int main() {
    int x, op, y, i;
    FILE* fin, *fout;
    fin = fopen("aib.in","r");
    fout = fopen("aib.out","w");
    fscanf(fin,"%d%d",&n,&m);
    for(i = 1; i <= n; i++) {
        fscanf(fin,"%d",&x);
        updateAIB(i,x);
    }
    for(i = 1; i <= m; i++) {
        fscanf(fin,"%d%d",&op,&x);
        if(op < 2)
            fscanf(fin,"%d",&y);
        if(op == 0)
            updateAIB(x,y);
        else if(op == 1)
            fprintf(fout,"%d\n",sum(y)-sum(x-1));
        else fprintf(fout,"%d\n",binarySearch(x));
    }
    fclose(fin);
    fclose(fout);
    return 0;
}