#include<bits/stdc++.h>
using namespace std;
using ll=long long;
template<typename T>
ostream& operator << (ostream &out,const vector<T>&x){
	if(x.empty())return out<<"[]";
	out<<'['<<x[0];
	for(int len=x.size(),i=1;i<len;i++)out<<','<<x[i];
	return out<<']';
}
template<typename T>
vector<T> ary(const T *a,int l,int r){
	return vector<T>{a+l,a+1+r};
}
template<typename T>
void debug(T x){
	cerr<<x<<'\n';
}
template<typename T,typename ...S>
void debug(T x,S ...y){
	cerr<<x<<' ',debug(y...);
}
const int N=1e4+10,mod=998244353;
int n,m,c[N];
ll a[N];
vector<int>to[N];
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)scanf("%d",&c[i]);
	for(int u,v;m--;){
		scanf("%d%d",&u,&v);
		to[u].push_back(v);
	}
	a[1]=1;
	int ans=1;
	for(int i=1;i<=n;i++){
		if(!a[i])continue;
		int v=c[i]/__gcd(a[i],(ll)c[i]);
		ans=1ll*ans*v;
		for(int j=i;j<=n;j++)a[j]*=v;
		for(int u=i;u<=n;u++){
			for(int v:to[u]){
				a[v]+=a[u]/c[u];
			}
			a[u]%=c[u];
		}
	}
	cout<<ans<<endl;
	return 0;
}