#include<cstdio>
#include<algorithm>
using namespace std;

#define lson l, mid, root<<1
#define rson mid+1, r, root<<1|1

const int N = 2000000 + 50;
struct node
{
    int l, r, mmax;
}a[4*N];

void build_tree(int l, int r, int root)
{
    a[root].l = l;
    a[root].r = r;
    if(l == r)
    {
        scanf("%d",&a[root].mmax);
        return ;
    }
    int mid = (l + r) >> 1;
    build_tree(lson);
    build_tree(rson);
    a[root].mmax = max(a[root<<1].mmax, a[root<<1|1].mmax);
}

void update(int l, int r, int root, int k)
{
    if(l == a[root].l && r == a[root].r)
    {
        a[root].mmax = k;
        return;
    }
    int mid = (a[root].l + a[root].r) >> 1;
    if(r <= mid)
        update(l, r, root<<1, k);
    else if(l > mid)
        update(l, r, root<<1|1, k);
    else
    {
        update(lson, k);
        update(rson, k);
    }
    a[root].mmax = max(a[root<<1].mmax, a[root<<1|1].mmax); //更新完单个点之后更新整棵树
}

int Query(int l, int r, int root)
{
    if(l == a[root].l && r == a[root].r)
        return a[root].mmax;
    int mid = (a[root].l + a[root].r) >> 1;
    if(r <= mid)
        return Query(l, r, root<<1);
    else if(l > mid)
        return Query(l, r, root<<1|1);
    else
        return max(Query(lson), Query(rson));
}

int main()
{
    int n, m, a, b;
    char ch[5];
    while(~scanf("%d%d",&n,&m))
    {
        build_tree(1, n, 1);
        while(m--)
        {
            getchar();
            scanf("%s%d%d",ch, &a, &b);
            if(ch[0] == 'Q')
                printf("%d\n",Query(a, b, 1));
            else
                update(a, a, 1, b);
        }
    }
    return 0;
}