#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;using LL=__int128;
const int N=4e5+5,M=2e6+5,K=(1<<15)+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const ll INF=1e18+7;mt19937 rnd(time(0));
int n,m,k,A[N],B[N],siz[N];
vector<int> f[N],ff[N];
multiset<int> g;
int l,r;
void Solve(){
	int i,j,h;scanf("%d%d",&n,&m);
	for(i=1;i<=n;i++) scanf("%d",&A[i]),siz[A[i]]++;
	k=siz[1];
	l=-siz[0];r=m-n+siz[0];
	f[-l+1].emplace_back(0);
	auto work=[&i](int ba,int h){
		ff[h]=f[h];
		for(int p:ff[h]) g.emplace(p-ba);
		if(ba>=siz[i]+1){
			for(int p:ff[h-(i-1)*(siz[i]+1)]) g.erase(g.LB(p-(ba-siz[i]-1)));
		}
		f[h].clear();
		int x=-1e9+7;
		while(1){
			auto p=g.LB(x+k+2);
			if(p!=g.begin()){
				auto q=p;q--;
				if(*q>x) {x=*q;f[h].emplace_back(x+ba);continue;} 
			}
			if(p==g.end()) break;
			x=*p;f[h].emplace_back(x+ba);
		}
	};
	for(i=m;~i;i--)if(i^1&&siz[i]){
		if(!i){
			g.clear();
			for(j=r-l+1;j;j--){
				int ba=r-l+1-j;
				work(ba,j);
			}
		}else{
			for(j=0;j<i-1;j++){
				g.clear();
				for(h=j;h<=r-l+1;h+=i-1){
					int ba=(h-j)/(i-1);
					work(ba,h);
				}
			}
		}
	}
	ll ans=0;
	for(int i=1;i<=r-l+1;i++){
		f[i].emplace_back(1e9+7);
		for(int j=0;j<f[i].size()-1;j++) ans+=min(f[i][j+1]-f[i][j],k+1);
	}
	printf("%lld\n",ans);
}
int main(){
	int t;
	// scanf("%d",&t);
	t=1;
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}