#include "stdio.h"

#include <cstdio>

#include <climits>

using namespace std;

#define M ((L+R)>>1)

#define lson rt<<1,L,M

#define rson rt<<1|1,M+1,R

#define root 1,1,N

#define max(a,b) ((a>b)?a:b)

const int maxn = 200001;

int maxv[maxn << 2],ql,qr,tar,v,val[maxn];

inline void pushup(int rt)

 {

    maxv[rt] = max(maxv[rt<<1],maxv[rt<<1|1]);

}

void build(int rt,int L,int R)

{

    if(L == R) maxv[rt] = val[L];

    else

    {

        build(lson); build(rson);

        pushup(rt);

    }

}

void update(int rt,int L,int R)

{

    if(L == R) maxv[rt] = v;

    else {

        if(tar <= M) update(lson);

        if(tar > M) update(rson);

        pushup(rt);

    }

}

int query(int rt,int L,int R)

{

    if(ql <= L && qr >= R) return maxv[rt];

    int lv = -INT_MAX,rv = -INT_MAX;

    if(ql <= M) lv = query(lson);

    if(qr > M) rv = query(rson);

    return max(lv,rv);

}

int main()

{

    int N,m;

    char cmd;

    while(~scanf("%d%d",&N,&m))

    {

        for(int i = 1;i <= N;i++)

        scanf("%d",val + i);

        build(root);

        for(int i = 1;i <= m;i++)

         {

            scanf(" %c",&cmd);

            if(cmd == 'Q')

             {

                scanf("%d%d",&ql,&qr);

                printf("%d\n",query(root));

            }

            else

            {

                scanf("%d%d",&tar,&v);

                update(root);

            }

        }

    }

    return 0;

}