///@author Sycamore ///@date 9/17/2017 ///@link http://acm.hdu.edu.cn/showproblem.php?pid=1754 #include
    
      using namespace std; const int MAXN = 200000 + 5; int val[MAXN]; struct node {
  int l, r, max_val; } ST[MAXN << 2]; void Build(int index, int l, int r) {
     ST[index].l = l;    ST[index].r = r;    if (l == r) ST[index].max_val = val[l];    else    {
  int m = (l + r) >> 1;       Build(index << 1, l, m);       Build((index << 1) + 1, m + 1, r);       ST[index].max_val = max(ST[index << 1].max_val, ST[(index << 1) + 1].max_val);    } } void Update(int n, int index, int id)//top-down {
  if (id < ST[index].l || id > ST[index].r) return;    if (ST[index].l == id && ST[index].r == id)    {
        ST[index].max_val = n;       return;    }    Update(n,index << 1, id);    Update(n,(index << 1) + 1, id);    ST[index].max_val = max(ST[index << 1].max_val, ST[(index << 1) + 1].max_val); } int Query(int l, int r, int index)//top-down {
  if (ST[index].l > r || ST[index].r 
     
      = l && ST[index].r <= r)return ST[index].max_val;    int m = (ST[index].l + ST[index].r) >> 1;    if (r <= m)return Query(l, r, index << 1);//in the left interval    if (l > m)return Query(l, r, (index << 1) + 1);    return max(Query(l, m, index << 1), Query(m + 1, r, (index << 1) + 1)); } #define endl '\n' int main() {
  ios::sync_with_stdio(false);    cin.tie(nullptr);    int n, m;    while (cin >> n >> m)    {
  for (int i = 1; i <= n; i++)cin >> val[i];       Build(1, 1, n);       char cmd;       while (m--)       {
           cin >> cmd;          if (cmd == 'Q')          {
  int l, r;             cin >> l >> r;             cout << Query(l, r, 1) << endl;          } else          {
  int a, id;             cin >> id >> a;             Update(a, 1, id);          }       }    } return 0; }