#include<bits/stdc++.h>
#define ri register signed
#define p(i) ++i
namespace IO{
    char buf[1<<21],*p1=buf,*p2=buf;
    #define gc() p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?(-1):*p1++
    struct nanfeng_stream{
        template<typename T>inline nanfeng_stream &operator>>(T &x) {
            ri f=1;x=0;register char ch=getchar();
            while(!isdigit(ch)) {if (ch=='-') x=-1;ch=getchar();}
            while(isdigit(ch)) {x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}
            return x=f?x:-x,*this;
        } 
    }cin;
}
using IO::cin;
namespace nanfeng{
    #define FI FILE *IN
    #define FO FILE *OUT
    template<typename T>inline T cmax(T x,T y) {return x>y?x:y;}
    template<typename T>inline T cmin(T x,T y) {return x>y?y:x;}
    static const int N=1e5+7;
    int first[N],w[N],ld[N],rd[N],B[N],fa[N],t=1,n,m,tot,ol,nm;
    char s[N];
    struct edge{int v,nxt;}e[N<<1];
    inline void add(int u,int v) {
        e[t].v=v,e[t].nxt=first[u],first[u]=t++;
        e[t].v=u,e[t].nxt=first[v],first[v]=t++;
    }
    void dfs(int x,int f) {
        ld[x]=p(tot);
        for (ri i(first[x]),v;i;i=e[i].nxt) {
            if ((v=e[i].v)==f) continue;
            fa[v]=x;
            dfs(v,x);
        }
        rd[x]=tot;
    }
    struct Seg{
        #define ls(x) (x<<1)
        #define rs(x) (x<<1|1)
        #define up(x) T[x].mx=cmax(T[ls(x)].mx,T[rs(x)].mx)
        struct segmenttree{int mx,lz;}T[N<<2];
        inline void down(int x) {
            if (!T[x].lz) return;
            T[ls(x)].mx=cmax(T[ls(x)].mx,T[x].lz);
            T[rs(x)].mx=cmax(T[rs(x)].mx,T[x].lz);
            T[ls(x)].lz=cmax(T[ls(x)].lz,T[x].lz);
            T[rs(x)].lz=cmax(T[rs(x)].lz,T[x].lz);
            T[x].lz=0;
        }
        int query(int x,int p,int l,int r) {
            if (l==r) return T[x].mx;
            int mid(l+r>>1);
            down(x);
            if (p<=mid) return query(ls(x),p,l,mid);
            else return query(rs(x),p,mid+1,r);
        }
        void update(int x,int k,int l,int r,int lt,int rt) {
            if (l<=lt&&rt<=r) {
                T[x].mx=cmax(T[x].mx,k);
                return (void)(T[x].lz=cmax(T[x].lz,k));
            }
            int mid(lt+rt>>1);
            down(x);
            if (l<=mid) update(ls(x),k,l,r,lt,mid);
            if (r>mid) update(rs(x),k,l,r,mid+1,rt);
            up(x);
        }
    }T;
    inline void update(int x) {
        ri nw=x,ns=x;
        T.update(1,w[x],ld[nw],rd[nw],1,n);
        B[nw]=1;
        nw=fa[nw];
        while(nw) {
            for (ri i(first[nw]),v;i;i=e[i].nxt) {
                if ((v=e[i].v)==ns||v==fa[nw]) continue;
                T.update(1,w[nw],ld[v],rd[v],1,n);
            }
            if (B[nw]) return;
            T.update(1,w[nw],ld[nw],ld[nw],1,n);
            B[nw]=1;
            ns=fa[ns],nw=fa[nw];
        }
    }
    inline int main() {
        //FI=freopen("nanfeng.in","r",stdin);
        //FO=freopen("nanfeng.out","w",stdout);
        cin >> n >> m;
        for (ri i(1);i<=n;p(i)) cin >> w[i];
        for (ri i(1),u,v;i<n;p(i)) cin >> u >> v,add(u,v);
        dfs(1,0); 
        for (ri i(1),v;i<=m;p(i)) {
            scanf("%s",s+1);
            cin >> v;
            if (s[1]=='Q') {
                if (!nm) puts("-1");
                else printf("%d\n",T.query(1,ld[v],1,n));
            } else p(nm),update(v);
        }
        return 0;
    }
}
int main() {return nanfeng::main();}