#include<bits/stdc++.h>
#define ll long long
using namespace std;
const ll p=998244353;
ll n,ans,a[500010],b[1000010],f[1000010],ny[1000010],c[1000010];
int main(){
	ll i,xlh,fm,sum;
	scanf("%lld",&n);
	for(i=1;i<=n;i++){
		scanf("%lld",&a[i]);
		b[a[i]]=b[a[i]]+a[i];c[a[i]]=(c[a[i]]+a[i]*a[i])%p;
	}
	ny[0]=ny[1]=1;
	for(i=2;i<=1000000;i++)ny[i]=ny[p%i]*(p-p/i)%p;
	for(fm=1000000;fm;fm--){
		xlh=0;sum=0;
		for(i=fm;i<=1000000;i+=fm)xlh=(xlh+c[i])%p,sum=(sum+b[i])%p;
		//if(xlh%2==0)xlh=xlh/2%p*(xlh+1);
		 //else xlh=(xlh+1)/2%p*xlh;
		xlh=(sum*sum%p-xlh+p)%p*ny[2]%p;
		//xlh=xlh*(xlh+1)%p*ny[2]%p;
		f[fm]=xlh;
		for(i=fm*2;i<=1000000;i+=fm)f[fm]=(f[fm]-f[i]+p)%p;
		//if(f[fm]>0)printf("%lld %lld\n",fm,f[fm]);
		ans=(ans+f[fm]*ny[fm])%p;
	}
	printf("%lld",ans);
}