#include <bits/stdc++.h>
#define mid ((l + r) >> 1)
#define lc(x) tr[x].l
#define rc(x) tr[x].r
#define sum(x) tr[x].sum
const int N = 8e4 + 10;
int n, m, q, bn, a[N], b[N], root[N], sz[N], f[N][25], dep[N], tot, last;
std::vector<int>e[N * 2];
struct node{
    int l, r, sum;
}tr[N * 150];
void change(int &x, int y, int l, int r, int pos) {
    x = ++tot;
    tr[x] = tr[y];
    tr[x].sum++;
    if(l == r) return;
    if(pos <= mid) change(lc(x), lc(y), l, mid, pos);
    else change(rc(x), rc(y), mid + 1, r, pos);
}
void dfs(int u, int fa, int p) {
    ++sz[p]; root[u] = p;
    change(root[u],root[fa],1,bn,a[u]);
    dep[u] = dep[fa] + 1; f[u][0] = fa;
    for(int i = 1; i <= 20; i++)  f[u][i] = f[f[u][i - 1]][i - 1];
    for(int v : e[u]) {
        if(v == fa) continue;
        dfs(v, u, p);
    }
}
int query(int u, int v, int x, int y, int l, int r, int k) {
    if(l == r) return b[l];
    int s = sum(lc(u)) + sum(lc(v)) - sum(lc(x)) - sum(lc(y));
    if(k <= s) return query(lc(u), lc(v), lc(x), lc(y), l, mid, k);
    else return query(rc(u), rc(v), rc(x), rc(y), mid + 1, r, k - s);
}
int LCA(int u,int v){
    if(dep[u] < dep[v]) std:: swap(u,v);
    for(int i = 20; i >= 0; i--) if(dep[f[u][i]] >= dep[v]) u = f[u][i];
    if(u == v) return u;
    for(int i = 20; i >= 0; i--) if(f[u][i] != f[v][i]) u = f[u][i], v = f[v][i];
    return f[u][0];
}
signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0); std:: cout.tie(0);
    int _; std:: cin >> _;
    std:: cin >> n >> m >> q;
    for(int i = 1; i <= n; i++) {
        std:: cin >> a[i];
        b[i] = a[i];
        root[i] = i;
    }
    std::sort(b + 1, b + n + 1);
    bn = std::unique(b + 1, b + n + 1) - b - 1;
    for(int i = 1; i <= n; i++) a[i] = std::lower_bound(b + 1, b + bn + 1, a[i]) - b;
    for(int i = 1; i <= m; i++) {
        int u, v; std:: cin >> u >> v;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    for(int i = 1; i <= n; i++) if(root[i] == i) dfs(i, 0, i);
    while(q--) {
        char tp; int x, y;
        std:: cin >> tp >> x >> y;
        x ^= last; y ^= last;
        if(tp == 'Q') {
            int k; std:: cin >> k; k ^= last;
            int lca = LCA(x, y), fa = f[lca][0];
            last = query(root[x], root[y], root[lca], root[fa], 1, bn, k);
            std:: cout << last << '\n';
        } else {
            e[x].push_back(y);
            e[y].push_back(x);
            if(sz[root[x]] > sz[root[y]]) dfs(y, x, root[x]);
            else dfs(x, y, root[y]);
        }
    }
}