#include <bits/stdc++.h>
#define rep(i,j,k) for(int i=(j);i<=(k);i++)
#define per(i,j,k) for(int i=(j);i>=(k);i--)
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define db double
#define ldb long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mkp make_pair
#define eb emplace_back
#define SZ(S) (int)S.size()
//#define mod 998244353
//#define mod 1000000007
#define inf 0x3f3f3f3f
#define linf 0x3f3f3f3f3f3f3f3f
using namespace std;

template <class T>
void chkmax(T &x,T y){
	if(x < y) x = y;
}

template <class T>
void chkmin(T &x,T y){
	if(x > y) x = y;
}

inline int popcnt(int x){
	return __builtin_popcount(x);
}

inline int ctz(int x){
	return __builtin_ctz(x);
}


/*ll power(ll p,int k = mod - 2){
	ll ans = 1;
	while(k){
		if(k % 2 == 1) ans = ans * p % mod;
		p = p * p % mod;
		k /= 2;	
	}
	return ans;
}*/
int n,m,tp,testid;
int a[500005];

#define lim 600
int _gcd[lim + 5][lim + 5];

ll buc[lim + 5],comb[lim + 5],res[500005];//buc 是小项的贡献,comb 是给小项的贡献
inline int calc(int x,int y){//assume x <= lim
	uint L = (uint)x * y / _gcd[x][y % x];
	return (m / L) * L;
}

int main(){
//	freopen("test.in","r",stdin);
//	freopen("test.out","w",stdout);
	rep(i,0,lim){
		_gcd[i][0] = i;
		rep(j,1,i) _gcd[i][j] = _gcd[j][i % j];
	}
	rep(i,0,lim){
		rep(j,i + 1,lim) _gcd[i][j] = _gcd[j][i];
	}

	scanf("%d%d%d%d",&n,&m,&tp,&testid);
	memset(buc,0xcf,sizeof(buc));
	memset(comb,0xcf,sizeof(comb));
	memset(res,0xcf,sizeof(res));
	ll cur,answer = 0;
	rep(i,1,n){
		scanf("%d",&a[i]);
		chkmin(a[i],m + 1);
		cur = answer;
		if(a[i] <= lim){
			chkmax(cur,comb[a[i]]);
		}else{
			rep(k,1,lim) chkmax(cur,buc[k] + calc(k,a[i]));
			for(int v = a[i];v <= m;v += a[i]) chkmax(cur,res[v]);
		}

		if(a[i] <= lim) chkmax(buc[a[i]],cur);
		rep(k,1,lim) chkmax(comb[k],cur + calc(k,a[i]));
		if(a[i] > lim) for(int v = a[i];v <= m;v += a[i]) chkmax(res[v],cur + (m / v) * v);
		chkmax(answer,cur);
	}
	printf("%lld\n",answer);
	return 0;
}