#include<fstream>
#include<algorithm>
#include<vector>

using namespace std;

const int Nmax = 100001;

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

int V[Nmax], N, M, Q, rad, lo, hi, poz, val;
vector<int> st, dr, arb;

void update() {

    int i, j;

    V[poz] = val;
    for(i=1; i<=Q; ++i)
        if(st[i] <= poz && poz <= dr[i]) {
            arb[i] = -1;
            for(j=st[i]; j<=dr[i]; ++j)
                arb[i] = max(arb[i], V[j]);
        }
}

int query() {

    int i, rez, left, right;

    rez = -1;
    left = 1<<30;
    right = -1;

    for(i=1; i<=Q; ++i)
        if(lo <= st[i] && dr[i] <= hi) {
            left = min(left, st[i]);
            right = max(right, dr[i]);
            rez = max(rez, arb[i]);
        }

    if(left == 1<<30 && right == -1)
        left = right = hi;

    for(i=lo; i<=left; ++i)
        rez = max(rez, V[i]);
    for(i=right; i<=hi; ++i)
        rez = max(rez, V[i]);

    return rez;
}

void build() {

    int i, j;

    for(rad=1; rad*rad<=N; ++rad);
    --rad;
    Q = N/rad + 1;

    st.resize(Q+1);
    dr.resize(Q+1);
    arb.resize(Q+1);

    for(i=1; i<=Q; ++i) {
        arb[i] = -1;
        st[i] = rad*(i-1)+1;
        dr[i] = rad*i;
        for(j=st[i]; j<=dr[i]; ++j)
            arb[i] = max(arb[i], V[j]);
    }
}

int main() {

    int i, op;

    f>>N>>M;
    for(i=1; i<=N; ++i)
        f>>V[i];

    build();

    while(M--) {
        f>>op;
        if(op == 0) {
            f>>lo>>hi;
            g<<query()<<"\n";
            continue;
        }
        if(op == 1) {
            f>>poz>>val;
            update();
            continue;
        }
    }

    f.close();
    g.close();

    return 0;
}