#include<bits/stdc++.h>
#define FILE "read"
#define MAXN (int)2e6+5
#define cmin(a,b) a=min(a,b)
#define cmax(a,b) a=max(a,b)
using namespace std;
typedef long long ll;
struct node{int y,next;}e[MAXN<<1];
int n,m,Q,cnt,len,top,bcnt,dfs_clock,sta[MAXN],Link[MAXN],deep[MAXN],dfn[MAXN],low[MAXN],anc[MAXN][25];
ll ans,v[MAXN],sumv[MAXN],sumvd[MAXN],sumvdd[MAXN];
vector<int>bcc[MAXN];
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 x*f;
}
void insert(int x,int y){
	e[++len].next=Link[x];Link[x]=len;e[len].y=y;
	e[++len].next=Link[y];Link[y]=len;e[len].y=x;
}
void tarjan(int x){
	dfn[x]=low[x]=++dfs_clock;  sta[++top]=x;
	for(int i=Link[x];i;i=e[i].next)if(!dfn[e[i].y]){
		tarjan(e[i].y);  cmin(low[x],low[e[i].y]);
		if(low[e[i].y]>=dfn[x]){
			bcnt++;  int y;
			do{
				y=sta[top--];
				bcc[bcnt].push_back(y);
			}while(y!=e[i].y);
			bcc[bcnt].push_back(x);
		}
	}else cmin(low[x],dfn[e[i].y]);
}
void dfs(int x,int fa){
	int flag=0;
	for(int i=Link[x];i;i=e[i].next)if(e[i].y!=fa&&e[i].y){
		deep[e[i].y]=deep[x]+1; anc[e[i].y][0]=x;
		sumv[e[i].y]=sumv[x]+v[e[i].y];
		sumvd[e[i].y]=sumvd[x]+v[e[i].y]*deep[e[i].y];
		sumvdd[e[i].y]=sumvdd[x]+v[e[i].y]*deep[e[i].y]*deep[e[i].y];
		dfs(e[i].y,x);  flag=1;
	}
	if(!flag){//叶子结点则新建方点
		insert(x,++cnt); deep[cnt]=deep[x]+1; anc[cnt][0]=x;
		sumv[cnt]=sumv[x]; sumvd[cnt]=sumvd[x]; sumvdd[cnt]=sumvdd[x];
	}
}
int LCA(int x,int y){
	if(deep[x]<deep[y])  swap(x,y);
	for(int i=20;i>=0;--i)  if(deep[anc[x][i]]>=deep[y])  x=anc[x][i];
	if(x==y)  return x;
	for(int i=20;i>=0;--i)  if(anc[x][i]!=anc[y][i])  x=anc[x][i],y=anc[y][i];
	return anc[x][0];
}
ll get(int x,int lca,int k){
	ll temp1=(sumv[x]-sumv[lca])*(k-deep[lca])*(deep[x]+1);
	ll temp2=(sumvd[x]-sumvd[lca])*(deep[x]+1-k+deep[lca]);
	ll temp3=sumvdd[x]-sumvdd[lca];
	return temp1+temp2-temp3;
}
int main(){
	freopen(FILE".in","r",stdin);
	freopen(FILE".out","w",stdout);
	int __size__=256<<20;
	char *__p__=(char*)malloc(__size__)+__size__;
	__asm__("movl %0, %%esp\n"::"r"(__p__));
	n=cnt=read(); m=read(); Q=read(); deep[1]=1;
	for(int i=1;i<=n;++i)  v[i]=read();
	for(int i=1;i<=m;++i){int x=read(),y=read();insert(x,y);}
	tarjan(1);  memset(Link,0,sizeof(Link));  len=0;
	for(int i=1;i<=bcnt;++i){
		++cnt; int size=bcc[i].size();
		for(int j=size-1;j>=0;--j)
			insert(cnt,bcc[i][j]);
	}
	sumv[1]=sumvd[1]=sumvdd[1]=v[1];
	dfs(1,0);  anc[1][0]=++cnt;
	for(int i=1;i<=20;++i)for(int x=1;x<=cnt;++x)
		anc[x][i]=anc[anc[x][i-1]][i-1];
	for(int T=1;T<=Q;++T){
		int x=read(),y=read(),lca=LCA(x,y);
		if(x==lca)  x=anc[x][0];
		else{
			for(int i=Link[x];i;i=e[i].next)if(e[i].y!=anc[x][0]&&e[i].y){x=e[i].y;break;}
		}
		if(y==lca)  y=anc[y][0];
		else{
			for(int i=Link[y];i;i=e[i].next)if(e[i].y!=anc[y][0]&&e[i].y){y=e[i].y;break;}
		}
		lca=LCA(x,y);
		int k1=deep[y]-deep[lca]+1,k2=deep[x]-deep[lca]+1;
		ans=get(x,lca,k1)+get(y,lca,k2)+v[lca]*k1*k2;
		printf("%lld\n",ans>>2);
	}
	return 0;
}