#include <iostream>
#include <stdio.h>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>
#include <cmath>

using namespace std;

typedef vector <int> VI;
typedef vector <VI> VVI;
typedef pair<int,int> PII;
typedef long long LL;

#define range(i,a,b) for(int i=(a); i < (b); i++)
#define rep(i,n) range(i,0,n)

#define P 1000000007

LL C[1001][1001];
int w[1000];
LL my_pow(LL b, LL e){
	LL ret = 1, prod = b;
	for (LL inc = e;inc>0;inc>>=1){
		if (inc&1){ret *= prod; ret %= P;}
		prod = prod * prod % P;
	}
	return ret;
}
LL calc(int i, int j){
	LL ret = 0;
	rep(k,w[j]){ret+=(k%2?-1:1)*(C[w[j]][k]*my_pow((LL)w[j]-k,(LL)w[i])%P);ret%=P;}
	return ret;
}
int main(){
	int N,M,x,y,w_min,h;
	LL ans = 0;
	VVI E;
	VI ::iterator it;
	PII tmp;
	map <int,int> V;
	priority_queue <PII, vector<PII> > Q;
	C[0][0] = 1;
	rep(i,1000) rep(j,i+1){
		C[i+1][j]+=C[i][j]; C[i+1][j]%=P;
		C[i+1][j+1]+=C[i][j]; C[i+1][j+1]%=P;
	}
	cin >> N >> M;
	E.resize(N);
	rep(i,N) cin >> w[i];
	rep(i,M){cin >> x >> y;E[--x].push_back(--y);}
	rep(s,N){
		V.clear();
		Q.push(PII(w[s],s));
		while (Q.size()>0){
			tmp = Q.top(); Q.pop();
			w_min = tmp.first; h = tmp.second;
			if (w_min <= V[h]) continue;
			V[h] = w_min;
			if(w[s]>=w[h] && w[h]<=w_min){ans += calc(s,h); ans %= P;} 
			w_min = min(w_min,w[h]);
			for (it=E[h].begin(); it!=E[h].end(); it++) Q.push(PII(w_min,*it));
		}
	}
	cout << ans << endl;
	return 0;
}