#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

#define maxn 200010

#define lson p<<1

#define rson p<<1|1

struct NOD

{

    int l,r;

    int best;

} node[maxn<<];

void build(int l,int r,int p)

{

    node[p].l = l,node[p].r = r;

    if(l == r)

    {

        scanf("%d",&node[p].best);

        return;

    }

    int mid = (l+r) >> ;

    build(l,mid,lson);

    build(mid+,r,rson);

    node[p].best = max(node[lson].best,node[rson].best);

}

int ask(int l,int r,int p)

{

    if(node[p].l == l && node[p].r == r)

    {

        return node[p].best;

    }

    int mid = (node[p].l+node[p].r)>>;

    if(r <= mid)

        return ask(l,r,lson);

    else if(l >= mid+)

        return ask(l,r,rson);

    else return max(ask(l,mid,lson),ask(mid+,r,rson));

}

void updata(int id,int num,int p)

{

    if(node[p].l==node[p].r && node[p].l == id)

    {

        node[p].best = num;

        return;

    }

    int mid = (node[p].l+node[p].r) >> ;

    if(id <= mid)

    updata(id,num,lson);

    else if(id > mid) updata(id,num,rson);

    node[p].best = max(node[lson].best,node[rson].best);

}

int main()

{

    int n,m;

    while(EOF!=scanf("%d%d",&n,&m))

    {

        build(,n,);

        while(m--)

        {

            char op[];

            scanf("%s",op);

            if(op[] == 'Q')

            {

                int l,r;

                scanf("%d%d",&l,&r);

                printf("%d\n",ask(l,r,));

            }

            else

            {

                int id,num;

                scanf("%d%d",&id,&num);

                updata(id,num,);

            }

        }

    }

    return ;

}