#include<bits/stdc++.h>
#define ls u<<1
#define rs u<<1|1
#define fi first
#define se second
#define min amin
#define max amax
#define pb push_back
#define pq priority_queue
#define vt vector
#define lb(x) (x&-x)
#define sub(i,j) ((1LL*i-1LL*j)%k+k)%k
std::mt19937 rnd(233);
using namespace std;
using ll=long long;
using node=pair<int,int>;
using nnode=array<int,3>;
//inline int read(){
//	int x=0,f=1;
//	char c=getchar();
//	while(c<'0'||c>'9'){
//		if(c=='-') f=-1;
//		c=getchar();
//	}
//	while(c>='0'&&c<='9'){
//		x=x*10+(c^'0');
//		c=getchar();
//	}
//	return x*f;
//}
template<typename T=int>T read(){T x;cin>>x;return x;}
template<typename U,typename V>auto min(U x,V y){return x<y?x:y;}
template<typename U,typename V>auto max(U x,V y){return x>y?x:y;}
template<typename U,typename...V>auto min(U x,V...y){return min(x,min(y...));}
template<typename U,typename...V>auto max(U x,V...y){return max(x,max(y...));}
template<typename U,typename V>bool cmin(U &x,V y){return x>y?x=y,true:false;}
template<typename U,typename V>bool cmax(U &x,V y){return x<y?x=y,true:false;}
constexpr int mod=998244353;
ll qpow(int x,int n=mod-2){ll y=1;for(;n;n>>=1,x=1LL*x*x%mod)if(n&1)y=1LL*y*x%mod;return y;}
//inline ll qpow(ll a, ll n=mod-2) { ll ans = 1;    while (n) { if (n & 1) { ans *= a; }a *= a; n >>= 1; }return ans; }
constexpr int N=1e5+10,M=3e7+10;
constexpr int inf=1e6;
ll n,a[N],x,ans,pre[N];
bool v[N];
void solve(){
	cin>>n>>x;
	for(int i=1;i<=n;++i)cin>>a[i];
	pre[1]=1;
	for(int i=2;i<=n;++i){
		if(a[i]==a[pre[i-1]]||a[i]+a[pre[i-1]]==x){
			v[i]=1,v[pre[i-1]]=1;
			++ans;
			pre[i]=pre[i-2];
		}
		else pre[i]=i;
	}
	int l=1,r=n;
	while(v[l])++l;
	while(v[r])--r;
	if(l<r){
		while(a[l]==a[r]||a[l]+a[r]==x)++ans,++l,--r;
	}
	cout<<ans<<'\n';
}
int main(){
	cin.sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
//	for(int T=read();T--;solve());
	solve();
}