#include
    
     #include
     
      #define L(x) (x << 1)#define R(x) (x << 1|1)#define MAX 200000typedef struct{    int left;    int right;    int temp_max;}Node;Node node[3*MAX];int max;int getmax(int x,int y){    return x 
      
       > 1;    build(l,mid,L(k));    build(mid+1,r,R(k));}void insert(int pos,int val,int k){    if(pos >= node[k].left && pos <= node[k].right)    {        node[k].temp_max = getmax(val,node[k].temp_max);    }    if(node[k].left == node[k].right)        return ;    if(pos < node[R(k)].left)        insert(pos,val,L(k));    else        insert(pos,val,R(k));}int get_result(int l,int r,int k){    if(l == node[k].left && r == node[k].right)    {        return max = node[k].temp_max;    }    if(node[k].left == node[k].right)        return max;    if(r < node[R(k)].left)        get_result(l,r,L(k));    else if(l > node[L(k)].right)        return get_result(l,r,R(k));    else        return max = getmax(get_result(l,node[L(k)].right,L(k)),get_result(node[R(k)].left,r,R(k)));}int main(){    int n,m,i,j,k;    char str[5];    while(~scanf("%d%d",&n,&m))    {        build(1,n,1);        memset(str,0,sizeof(str));        for(i = 1;i <= n;i ++)        {            scanf("%d",&j);            insert(i,j,1);        }        for(i = 1;i <= m;i ++)        {            scanf("%s",str);            if(!strcmp(str,"Q"))            {                max = 0;                scanf("%d%d",&j,&k);                get_result(j,k,1);                printf("%d\n",max);            }            else            {                scanf("%d%d",&j,&k);                insert(j,k,1);            }            memset(str,0,sizeof(str));        }    }    return 0;}