#include <bits/stdc++.h>
using namespace std;
inline int read() {
  register int x = 0, t = 1;
  register char ch = getchar();
  while ((ch < '0' || ch > '9') && ch != '-') ch = getchar();
  if (ch == '-') t = -1, ch = getchar();
  while (ch <= '9' && ch >= '0') x = x * 10 + ch - 48, ch = getchar();
  return x * t;
}
struct Line {
  int v, next;
};
struct Link {
  Line e[444444 << 1];
  int h[444444], cnt;
  void Add(int u, int v) {
    e[++cnt] = (Line){v, h[u]};
    h[u] = cnt++;
    e[++cnt] = (Line){u, h[v]};
    h[v] = cnt++;
  }
} Gr, Tr;
multiset<int> MS[444444];
int W[444444];
int n, m, Q, Tot;
struct Graph {
  int dfn[444444], low[444444], S[444444], tim, top;
  void Tarjan(int u) {
    dfn[u] = low[u] = ++tim;
    S[++top] = u;
    for (int i = Gr.h[u]; i; i = Gr.e[i].next) {
      int v = Gr.e[i].v;
      if (!dfn[v]) {
        Tarjan(v);
        low[u] = min(low[u], low[v]);
        if (low[v] >= dfn[u]) {
          Tr.Add(++Tot, u);
          int x;
          do {
            x = S[top--];
            Tr.Add(Tot, x);
          } while (v != x);
        }
      } else
        low[u] = min(low[u], dfn[v]);
    }
  }
} G;
struct SegMentTree {
  int t[444444 << 2];
  void Modify(int now, int l, int r, int p, int w) {
    if (l == r) {
      t[now] = w;
      return;
    }
    int mid = (l + r) >> 1;
    if (p <= mid)
      Modify((now << 1), l, mid, p, w);
    else
      Modify((now << 1 | 1), mid + 1, r, p, w);
    t[now] = min(t[(now << 1)], t[(now << 1 | 1)]);
  }
  int Query(int now, int l, int r, int L, int R) {
    if (L <= l && r <= R) return t[now];
    int ret = 1e9, mid = (l + r) >> 1;
    if (L <= mid) ret = min(ret, Query((now << 1), l, mid, L, R));
    if (R > mid) ret = min(ret, Query((now << 1 | 1), mid + 1, r, L, R));
    return ret;
  }
} SMT;
int fa[444444], tim, dfn[444444], low[444444];
int size[444444], hson[444444], top[444444], dep[444444];
void dfs1(int u, int ff) {
  fa[u] = ff;
  dep[u] = dep[ff] + 1;
  size[u] = 1;
  if (u <= n && ff) MS[ff].insert(W[u]);
  for (int i = Tr.h[u]; i; i = Tr.e[i].next) {
    int v = Tr.e[i].v;
    if (v == ff) continue;
    dfs1(v, u);
    size[u] += size[v];
    if (size[v] > size[hson[u]]) hson[u] = v;
  }
}
void dfs2(int u, int tp) {
  top[u] = tp;
  dfn[u] = ++tim;
  low[tim] = u;
  if (hson[u]) dfs2(hson[u], tp);
  for (int i = Tr.h[u]; i; i = Tr.e[i].next)
    if (Tr.e[i].v != fa[u] && Tr.e[i].v != hson[u]) dfs2(Tr.e[i].v, Tr.e[i].v);
}
int Query(int u, int v) {
  int ret = 1e9;
  while (top[u] ^ top[v]) {
    if (dep[top[u]] < dep[top[v]]) swap(u, v);
    ret = min(ret, SMT.Query(1, 1, Tot, dfn[top[u]], dfn[u]));
    u = fa[top[u]];
  }
  if (dep[u] > dep[v]) swap(u, v);
  ret = min(ret, SMT.Query(1, 1, Tot, dfn[u], dfn[v]));
  if (u <= n)
    return ret;
  else
    return min(ret, W[fa[u]]);
}
void Modify(int u, int w) {
  if (fa[u]) {
    MS[fa[u]].erase(MS[fa[u]].find(W[u]));
    MS[fa[u]].insert(w);
    SMT.Modify(1, 1, Tot, dfn[fa[u]], *MS[fa[u]].begin());
  }
  W[u] = w;
  SMT.Modify(1, 1, Tot, dfn[u], w);
}
int main() {
  Tot = n = read();
  m = read();
  Q = read();
  W[0] = 1e9;
  for (int i = 1; i <= n; ++i) W[i] = read();
  for (int i = 1; i <= m; ++i) Gr.Add(read(), read());
  G.Tarjan(1);
  dfs1(1, 0);
  dfs2(1, 1);
  for (int i = 1; i <= n; ++i) SMT.Modify(1, 1, Tot, dfn[i], W[i]);
  for (int i = n + 1; i <= Tot; ++i)
    SMT.Modify(1, 1, Tot, dfn[i], *MS[i].begin());
  char ch[2];
  while (Q--) {
    scanf("%s", ch);
    int a = read(), b = read();
    if (ch[0] == 'C')
      Modify(a, b);
    else
      printf("%d\n", Query(a, b));
  }
  return 0;
}
