#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];
int ind[maxn + 5];
int V[maxn + 5];
int tp[maxn + 5];
i64 ca[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);
	}
	queue<int> q;
	for (int i = 1; i <= n; i++)
		if (!ind[i]) q.push(i);
	int cnt = 0;
	while (!q.empty()) {
		int u = q.front(); q.pop();
		tp[++cnt] = u;
		for (int v : g[u])
			if (!(--ind[v])) q.push(v);
	}
	i64 ans = c[1];
	for (int v : g[1]) V[v] = 1;
	for (int i = 2; i <= n; i++) {
		int u = tp[i];
		if (!V[u]) continue;
		int t = c[u] / gcd(c[u], V[u]);
		ans *= t;
		memset(ca, 0, sizeof(ca));
		for (int j = 1; j <= n; j++) {
			int u2 = tp[j];
			i64 p = 1LL * V[u2] * t + ca[u2];
			V[u2] = p % c[u2];
			for (int v : g[u2]) ca[v] += p / c[u2];
		}
	}
	printf("%lld", ans);
}