#include <bits/stdc++.h>
using namespace std;
const int N = 200005;
const int M = 400005;
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return f * x;
}
int n, m, q, num;
int hd[N], nxt[M], to[M], tot;
inline void add(int x, int y) {
  to[++tot] = y;
  nxt[tot] = hd[x];
  hd[x] = tot;
}
int dfn[N], low[N], dfn_cnt;
int st[N], tp;
bool vis[N];
vector<int> G[N];
void tarjan(int x) {
  vis[x] = 1;
  st[++tp] = x;
  dfn[x] = low[x] = ++dfn_cnt;
  for (int i = hd[x]; i; i = nxt[i]) {
    int y = to[i];
    if (!dfn[y]) {
      tarjan(y);
      low[x] = min(low[x], low[y]);
      if (low[y] == dfn[x]) {
        ++num;
        while (st[tp + 1] != y) {
          G[num].push_back(st[tp]);
          G[st[tp]].push_back(num);
          vis[st[tp--]] = 0;
        }
        G[num].push_back(x);
        G[x].push_back(num);
      }
    } else if (vis[y])
      low[x] = min(low[x], dfn[y]);
  }
}
multiset<int> s[N];
int siz[N], fa[N], dep[N], son[N];
void dfs_son(int x, int f) {
  fa[x] = f;
  siz[x] = 1;
  dep[x] = dep[f] + 1;
  for (int i = 0; i < G[x].size(); i++) {
    int y = G[x][i];
    if (y == f) continue;
    dfs_son(y, x);
    siz[x] += siz[y];
    if (siz[y] > siz[son[x]]) son[x] = y;
  }
}
int rev[N], top[N];
void dfs_chain(int x, int tp) {
  top[x] = tp;
  dfn[x] = ++dfn_cnt;
  rev[dfn_cnt] = x;
  if (son[x]) dfs_chain(son[x], tp);
  for (int i = 0; i < G[x].size(); i++) {
    int y = G[x][i];
    if (y == fa[x] || y == son[x]) continue;
    dfs_chain(y, y);
  }
}
int val[N << 2];
int w[N];
void build(int l, int r, int p) {
  if (l == r) {
    val[p] = w[rev[l]];
    return;
  }
  build(l, ((l + r) >> 1), (p << 1));
  build(((l + r) >> 1) + 1, r, (p << 1 | 1));
  val[p] = min(val[(p << 1)], val[(p << 1 | 1)]);
}
void modify(int l, int r, int t, int v, int p) {
  if (l == r) {
    val[p] = v;
    return;
  }
  if (t <= ((l + r) >> 1))
    modify(l, ((l + r) >> 1), t, v, (p << 1));
  else
    modify(((l + r) >> 1) + 1, r, t, v, (p << 1 | 1));
  val[p] = min(val[(p << 1)], val[(p << 1 | 1)]);
}
int query(int l, int r, int L, int R, int p) {
  if (L <= l && r <= R) return val[p];
  int ans = 0x3f3f3f3f;
  if (L <= ((l + r) >> 1))
    ans = min(ans, query(l, ((l + r) >> 1), L, R, (p << 1)));
  if (R > ((l + r) >> 1))
    ans = min(ans, query(((l + r) >> 1) + 1, r, L, R, (p << 1 | 1)));
  return ans;
}
int get_min(int x, int y) {
  int ans = 0x3f3f3f3f;
  while (top[x] != top[y]) {
    if (dep[top[x]] < dep[top[y]]) swap(x, y);
    ans = min(ans, query(1, num, dfn[top[x]], dfn[x], 1));
    x = fa[top[x]];
  }
  if (dfn[x] > dfn[y]) swap(x, y);
  ans = min(ans, query(1, num, dfn[x], dfn[y], 1));
  if (x > n) ans = min(ans, w[fa[x]]);
  return ans;
}
int main() {
  n = read();
  m = read();
  q = read();
  for (int i = 1; i <= n; i++) w[i] = read();
  num = n;
  for (int i = 1, x, y; i <= m; i++) {
    x = read();
    y = read();
    add(x, y), add(y, x);
  }
  tarjan(1);
  dfn_cnt = 0;
  dfs_son(1, 0);
  dfs_chain(1, 1);
  for (int i = 1; i <= n; i++)
    if (fa[i]) s[fa[i]].insert(w[i]);
  for (int i = n + 1; i <= num; i++) w[i] = *s[i].begin();
  memset(val, 0x3f, sizeof(val));
  build(1, num, 1);
  char op;
  int x, y;
  while (q--) {
    cin >> op;
    x = read();
    y = read();
    if (op == 'C') {
      modify(1, num, dfn[x], y, 1);
      if (fa[x]) {
        s[fa[x]].erase(s[fa[x]].lower_bound(w[x]));
        s[fa[x]].insert(y);
        if (w[fa[x]] != *s[fa[x]].begin()) {
          w[fa[x]] = *s[fa[x]].begin();
          modify(1, num, dfn[fa[x]], w[fa[x]], 1);
        }
      }
      w[x] = y;
    } else
      printf("%d\n", get_min(x, y));
  }
  return 0;
}
