#include <bits/stdc++.h>
#define pt(sth) cout << sth << "\n"
#define itr(x,c) for(auto x=c.begin();x!=c.end();x++)
#define all(a) (a.begin()),(a.end())
using namespace std;
#include <atcoder/all>
using namespace atcoder;
typedef long long ll;
typedef pair<ll, ll> pll;
template<class T>bool chmax(T &a, const T &b) {if(a<b) {a=b; return 1;} return 0;}
template<class T>bool chmin(T &a, const T &b) {if(b<a) {a=b; return 1;} return 0;}
static const ll INF=1e18;
static const ll MAX=101010;
//static const ll MOD=1e9+7;
//static const ll MOD=998244353;
//for(i=0;i<N;i++) cin>>a[i];

typedef vector<ll> v1D;
typedef vector<v1D> v2D;
typedef vector<v2D> v3D;



int main(void) {
  ll i,j,k;
  
  ll N,M,S,T;cin>>N>>M>>S>>T;S--;T--;
  
  dsu d(N);
  vector<ll> a(N);
  for(i=0;i<N;i++)cin>>a[i];
  
  for(i=0;i<M;i++){
    ll x,y;cin>>x>>y;x--;y--;
    d.merge(x, y);
  }
  
  set<ll> st;
  for(i=0;i<N;i++)
    if(d.leader(i)==d.leader(S) and a[i]<a[S])
      st.insert(a[i]);
  st.insert(a[S]);
  
  pt((ll)st.size()-1);
  
  
  
  
  
  
  
}