//#pragma GCC target ("avx") //#pragma GCC optimize("Ofast") //#pragma GCC optimize("unroll-loops") //#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") #define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using ll = long long; using ld = long double; using H = pair; using P = pair; using vi = vector; #define all(a) (a).begin(),(a).end() #define fs first #define sc second #define xx first #define yy second.first #define zz second.second #define Q(i,j,k) mkp((i),mkp((j),(k))) #define rng(i,s,n) for(ll i = (s) ; i < (n) ; i++) #define rep(i,n) rng(i, 0, (n)) #define mkp make_pair #define vec vector #define pb emplace_back #define siz(a) int((a).size()) #define crdcomp(b) sort(all((b)));(b).erase(unique(all((b))),(b).end()) #define getidx(b,i) (lower_bound(all((b)),(i))-(b).begin()) #define ssp(i,n) (i==(ll)(n)-1?"\n":" ") #define ctoi(c) (int)((c)-'0') #define itoc(c) (char)((c)+'0') #define cyes printf("Yes\n") #define cno printf("No\n") #define cdf(n) for(int quetimes_=(n);quetimes_>0;quetimes_--) #define gcj printf("Case #%lld: ",quetimes_+1) #define readv(a,n) (a).resize((n),0);rep(i,(n)) (a)[i]=read() #define found(a,x) (a.find(x)!=a.end()) constexpr ll mod = (ll)1e9 + 7; constexpr ll Mod = 998244353; constexpr ld EPS = 1e-10; constexpr ll inf = (ll)3 * 1e18; constexpr int Inf = (ll)15 * 1e8; constexpr int dx[] = { -1,1,0,0 }, dy[] = { 0,0,-1,1 }; templatebool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; } templatebool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; } ll read() { ll u, k = scanf("%lld", &u); return u; } string reads() { string s; cin >> s; return s; } H readh(short g = 0) { H u; int k = scanf("%lld %lld", &u.fs, &u.sc); if (g == 1) u.fs--, u.sc--; if (g == 2) u.fs--; return u; } bool ina(H t, int h, int w) { return 0 <= t.fs && t.fs < h && 0 <= t.sc && t.sc < w; } bool ina(int t, int l, int r) { return l <= t && t < r; } ll gcd(ll i, ll j) { return j ? gcd(j, i % j) : i; } ll ppc(ll x) { int sum = 0; for (int i = 0; i < 60; i++)if ((1ll << i) & x) sum++; return sum; } template void fin(T x) { cout << x << endl; exit(0); } template class csum { vec v; public: csum(vec& a) :v(a) { build(); } csum() {} csum(int sz) { init(sz); } void init(int sz) { v = vector(sz + 1, 0); } void init(vec& a) { v = a; build(); } void build() { for (int i = 1; i < v.size(); i++) v[i] += v[i - 1]; } void add(int l, int r, T x) { v[l] += x; v[r] -= x; }//[l,r) void add(int t, T x) { v[t] += x; }//[l,r) //[l,r] T a(int l, int r) { if (r < l) return 0; return v[r] - (l == 0 ? 0 : v[l - 1]); } //[l,r) T b(int l, int r) { return a(l, r - 1); } T a(pairt) { return a(t.first, t.second); } T b(pairt) { return b(t.first, t.second); } T operator[](int x)const { return v[x]; } }; template class modint { public:ll v; modint(ll v = 0) { s(v % mod + mod); } constexpr static int fn_ = (ll)2e6 + 5; static vectorfact, comp; modint pow(ll x) const { modint b(v), c(1); while (x) { if (x & 1) c *= b; b *= b; x >>= 1; } return c; } inline modint& s(int vv) { v = vv < mod ? vv : vv - mod; return *this; } inline modint inv()const { return pow(mod - 2); } inline modint operator-()const { return modint() - *this; } inline modint& operator+=(const modint b) { return s(v + b.v); } inline modint& operator-=(const modint b) { return s(v + mod - b.v); } inline modint& operator*=(const modint b) { v = v * b.v % mod; return *this; } inline modint& operator/=(const modint b) { v = v * b.inv().v % mod; return *this; } inline modint operator+(const modint& b) const { return modint(v) += b; } inline modint operator-(const modint& b) const { return modint(v) -= b; } inline modint operator*(const modint& b) const { return modint(v) *= b; } inline modint operator/(const modint& b) const { return modint(v) /= b; } friend ostream& operator<<(ostream& os, const modint& m) { return os << m.v; } friend istream& operator>>(istream& is, modint& m) { int x; is >> x; m = modint(x); return is; } bool operator<(const modint& r)const { return v < r.v; } bool operator>(const modint& r)const { return v > r.v; } bool operator<=(const modint& r)const { return v <= r.v; } bool operator>=(const modint& r)const { return v >= r.v; } bool operator==(const modint& r)const { return v == r.v; } bool operator!=(const modint& r)const { return v != r.v; } explicit operator bool()const { return v; } explicit operator int()const { return v; } modint comb(modint k) { if (k > *this) return modint(); if (fact.empty()) combinit(); if (v >= fn_) { if (k > *this - k) k = *this - k; modint tmp(1); for (int i = v; i >= v - k.v + 1; i--) tmp *= modint(i); return tmp * comp[k.v]; } return fact[v] * comp[k.v] * comp[v - k.v]; }//nCk modint perm(modint k) { if (k > *this) return modint(); if (fact.empty()) combinit(); if (v >= fn_) { modint tmp(1); for (int i = v; i >= v - k.v + 1; i--) tmp *= modint(i); return tmp; } return fact[v] * comp[v - k.v]; }//nPk static void combinit() { fact.assign(fn_, modint()); fact[0] = 1; for (int i = 1; i < fn_; i++) fact[i] = fact[i - 1] * modint(i); comp.assign(fn_, modint()); comp[fn_ - 1] = fact[fn_ - 1].inv(); for (int i = fn_ - 2; i >= 0; i--) comp[i] = comp[i + 1] * modint(i + 1); } }; using mint = modint; template<>vec mint::fact = vec(); template<>vec mint::comp = vec(); //-------------------------------------------------------------- template class BIT { int size; vectordat; public: BIT() {} BIT(vectorv) { init(v); } BIT(int n) { init(n); } void init(int n) { size = n; dat.assign(size + 1, 0); } void init(vectorv) { init(v.size()); for (int i = 1; i <= size; i++) { dat[i] += v[i - 1]; if (i + (i & -i) <= size) dat[i + (i & -i)] += dat[i]; } } void add(int i, ll x) { i++; while (i <= size) { chmax(dat[i], x); i += i & -i; } } void change(int i, ll x) { i++; int t = x - dat[i]; while (i <= size) { int k = dat[i]; dat[i] += t; t = dat[i] - k; i += i & -i; } } //[l,r) void add(int l, int r, ll x) { add(l, x); add(r, -x); } //[0,i] T query(int i) { i++; T sum = 0; while (i > 0) { chmax(sum, dat[i]); i -= i & -i; } return sum; } //[l,r) T query(int l, int r) { return query(r - 1) - query(l - 1); } //[0,x) >= w int lower_bound(T w) { if (w <= 0) return 0; int x = 0, k = 1; while (k * 2 < size) k *= 2; for (; k > 0; k /= 2) { if (x + k <= size && dat[x + k] < w) { w -= dat[x + k]; x += k; } } return x; } };//size, 0-indexed class unionfind { int size = 0, grps = 0; vectorpa; public: unionfind() {} unionfind(int n) { init(n); } void init(int n) { size = n, grps = n; pa.assign(n, -1); } int root(int x) { if (pa[x] < 0) return x; return pa[x] = root(pa[x]); } bool unite(int x, int y) { x = root(x); y = root(y); if (x == y) return false; grps--; if (pa[x] > pa[y]) swap(x, y); pa[x] += pa[y]; pa[y] = x; return true; } bool same(int x, int y) { return root(x) == root(y); } bool isroot(int x) { return x == root(x); } int sz(int x) { return -pa[root(x)]; } int groups() { return grps; } H operator[](int x) { x = root(x); return H{ x,-pa[x] }; } }; //-------------------------------------------------------------- vi e[200000]; signed main() { int n, m, s, t; cin >> n >> m >> s >> t; s--; t--; vi a; readv(a, n); rep(i, m) { int u, v; cin >> u >> v; u--; v--; e[u].pb(v); e[v].pb(u); } unionfind uf(n); vecb; rep(i, n) b.pb(H{ a[i],i }); sort(all(b), greater()); int ans = 0, x = a[s]; rep(i, n) { int t = b[i].sc; for (auto g : e[t]) { if (a[g] < a[t]) continue; uf.unite(g, t); } if (a[t] < x && uf.same(s, t)) ans++; } cout << ans << endl; }