#include <bits/stdc++.h>
#define PB push_back
#define EB emplace_back
#define gcd(x, y) __gcd(x, y)
using namespace std;
typedef long long i64;
const int maxn = 10000;
int c[maxn + 5];
vector<int> g[maxn + 5], g2[maxn + 5];
bool vis[maxn + 5];
void dfs(int u) {
	vis[u] = 1;
	for (int v : g[u])
		if (!vis[v]) dfs(v);
}
int ind[maxn + 5];
i64 ca[maxn + 5];
int tp[maxn + 5];
int main() {
	int n, m;
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++) scanf("%d", &c[i]);
	for (int i = 1; i <= m; i++) {
		int u, v;
		scanf("%d%d", &u, &v);
		g[u].PB(v), g2[v].PB(u);
	}
	dfs(1);
	for (int u = 1; u <= n; u++)
		if (vis[u])
			for (int v : g[u]) ind[v]++;
	queue<int> q;
	i64 ans = c[1];
	ca[1] = tp[1] = 1;
	for (int v : g[1])
		if (!(--ind[v])) q.push(v);
	for (int i = 2; !q.empty(); i++) {
		int u = q.front(); q.pop();
		tp[i] = u;
		i64 s = 0;
		for (int v : g2[u]) s += ca[v];
		if (s < 0) cout << "FAT" << endl;
		int t = c[u] / gcd(s, 1LL * c[u]);
		if (t < 0) cout << "FAT2" << endl;
		ca[u] = t * s / c[u];
		ans *= t;
		for (int j = 1; j < i; j++) ca[tp[j]] *= t;
		for (int v : g[u])
			if (!(--ind[v])) q.push(v);
	}
	printf("%lld", ans);
}