#include<bits/stdc++.h>
#define reg register int
#define mid ((l+r)>>1)
#define il inline
#define numb (ch^'0')
using namespace std;
typedef long long ll;
il void rd(int &x){char ch;x=0;bool fl=false;while(!isdigit(ch=getchar()))(ch=='-')&&(fl=true);for(x=numb;isdigit(ch=getchar());x=x*10+numb);(fl==true)&&(x=-x);
}
namespace Miracle{
const int N=2e5+5;
const int inf=0x3f3f3f3f;
int n,m,q;
struct node{int nxt,to;
}e[2*N],bian[2*N];
int hd[N],pre[N];
int cnt1,cnt2;
void _add(int x,int y){bian[++cnt1].nxt=pre[x];bian[cnt1].to=y;pre[x]=cnt1;
}
void add(int x,int y){e[++cnt2].nxt=hd[x];e[cnt2].to=y;hd[x]=cnt2;
}
struct heap{priority_queue<int,vector<int>,greater<int> >h,d;int top(){while(h.size()&&d.size()&&h.top()==d.top()){h.pop();d.pop();}if(h.empty()) return inf;return h.top();}void push(int c){h.push(c);}void dele(int c){d.push(c);}
}f[N];
int w[N];
int tot,df;
int dfn[N],low[N],sta[N],tp;
void tarjan(int x){dfn[x]=low[x]=++df;sta[++tp]=x;for(reg i=pre[x];i;i=bian[i].nxt){int y=bian[i].to;if(!dfn[y]){tarjan(y);low[x]=min(low[x],low[y]);if(dfn[x]<=low[y]){++tot;//fangw[tot]=inf;//warning!!!int z;do{z=sta[tp--];add(tot,z);add(z,tot);}while(z!=y);add(x,tot);add(tot,x);}}else low[x]=min(low[x],dfn[y]);}
}
int dep[N],fa[N],top[N],fdfn[N],son[N],sz[N];
void dfs1(int x,int d){dep[x]=d;sz[x]=1;for(reg i=hd[x];i;i=e[i].nxt){int y=e[i].to;if(y==fa[x]) continue;fa[y]=x;dfs1(y,d+1);sz[x]+=sz[y];if(sz[y]>sz[son[x]]) son[x]=y;if(x>n){//a fang
            f[x].push(w[y]);w[x]=min(w[x],w[y]);}}
}
void dfs2(int x){dfn[x]=++df;fdfn[df]=x;if(!top[x]) top[x]=x;if(son[x]) top[son[x]]=top[x],dfs2(son[x]);for(reg i=hd[x];i;i=e[i].nxt){int y=e[i].to;if(y==fa[x]) continue;if(y==son[x]) continue;dfs2(y);}
}
int mi[4*N];
void pushup(int x){mi[x]=min(mi[x<<1],mi[x<<1|1]);
}
void build(int x,int l,int r){if(l==r){mi[x]=w[fdfn[l]];return;}build(x<<1,l,mid);build(x<<1|1,mid+1,r);pushup(x);
}
void chan(int x,int l,int r,int to,int c){if(l==r){mi[x]=c;return;}if(to<=mid) chan(x<<1,l,mid,to,c);else chan(x<<1|1,mid+1,r,to,c);pushup(x);
}
int query(int x,int l,int r,int L,int R){if(L<=l&&r<=R){return mi[x];}int ret=inf;if(L<=mid) ret=min(ret,query(x<<1,l,mid,L,R));if(mid<R) ret=min(ret,query(x<<1|1,mid+1,r,L,R));return ret;
}
int wrk(int x,int y){int ret=inf;while(top[x]!=top[y]){if(dep[top[x]]<dep[top[y]]) swap(x,y);ret=min(ret,query(1,1,tot,dfn[top[x]],dfn[x]));x=fa[top[x]];}if(dep[x]<dep[y]) swap(x,y);ret=min(ret,query(1,1,tot,dfn[y],dfn[x]));if(y>n) ret=min(ret,w[fa[y]]);return ret;
}
int main(){rd(n);rd(m);rd(q);for(reg i=1;i<=n;++i)rd(w[i]);int x,y;for(reg i=1;i<=m;++i){rd(x);rd(y);_add(x,y);_add(y,x);}tot=n;tarjan(1);memset(dfn,0,sizeof dfn);df=0;dfs1(1,1);dfs2(1);build(1,1,tot);char ch[10];while(q--){scanf("%s",ch+1);if(ch[1]=='A'){rd(x);rd(y);printf("%d\n",wrk(x,y));}else{rd(x);rd(y);int ff=fa[x];f[ff].dele(w[x]);f[ff].push(y);int tmp=f[ff].top();chan(1,1,tot,dfn[ff],tmp);w[ff]=tmp;//no use in factw[x]=y;chan(1,1,tot,dfn[x],y);}}return 0;
}}
int main(){Miracle::main();return 0;
}/*Author: *Miracle*Date: 2018/11/30 16:10:40
*/