#include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 5;

typedef long long ll;

inline int read() {
	register char ch = getchar(); register int s = 0, f = 1;
	while (!isdigit(ch)) f = (ch == '-' ? -1 : 1), ch = getchar();
	while (isdigit(ch)) s = (s * 10) + (ch & 15), ch = getchar();
	return s * f; 
}

int n, m;
ll c[N], f[N];
vector<int> e[N];

inline ll gcd(ll a, ll b) {
	return !b ? a : gcd(b, a % b);
}

int main() {
	n = read(); m = read();
	for (int i = 1; i <= n; ++i) c[i] = read();
	for (int i = 1, u, v; i <= m; ++i) {
		u = read(); v = read();
		e[u].push_back(v);
	} f[1] = 1; ll res = 1;
	for (int i = 1; i <= n; ++i) {
		ll k = c[i] / gcd(c[i], f[i]); res *= k;
		for (int j = i; j <= n; ++j) f[j] *= k;
		for (int j = i; j <= n; ++j) {
			for (int v : e[j])
				f[v] += f[j] / c[j];
			f[j] %= c[j];
		}
	} printf("%lld\n", res);
	return 0;
}