#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;
typedef vector<ll> vll;
#define FOR(i,n) for (i = 0; i < n; ++i)
#define FORK(i,k,n) for (i = k; i <= n; ++i)
#define FORR(i,k,n) for (i = k; i >= n; --i)

#define re(a,b)   memset(a,b,sizeof(a))
#define sz(a)      (int)(a.size())
#define MIN(a,b)     (a) = min((a),(b))
#define MAX(a,b)     (a) = max((a),(b))
#define input(in)    freopen(in,"r",stdin)
#define output(out)  freopen(out,"w",stdout)
#define ALL(a)       a.begin(),a.end()
#define RALL(a)      a.rbegin(),a.rend()
#define LEN(a)       (int)(a.length())

#define FIN(x)       freopen(x,"r",stdin)
#define FOUT(x)      freopen(x,"w",stdout)
#define FCLOSE       {fclose(stdin); fclose(stdout);}

#define fi           first
#define se           second
#define pb           push_back
#define mp           make_pair
#define  M           1000010
#define INF          1001001001

ll visit[M];// for counting the elements
void update(ll i,ll v,ll b[],ll n)
{
    for(; i <=n; i += i&-i)
        b[i] += v;
}
ll query(ll x,ll b[])
{
     ll sum = 0;
     for(; x > 0; x -= x&-x)
        sum += b[x];
     return sum;
}
template<class T> 	//fast I/O operations
inline void inp(T &p) {
    p=0; register char ch=0;
    while(ch<'0' or ch>'9') {ch=getchar();}
    while(ch>='0' and ch<='9') {p=(p<<1)+(p<<3)+ch-'0'; ch=getchar();}
}
int main()
{
   // ios_base::sync_with_stdio(false);cin.tie(0);
    ll i,j,n,x,y,k;
    inp(n);
    inp(k);
    ll pi[n]={0},t[n];
    ll ans=0;
    vector<ll> a;
    FOR(i,n)
    {
        inp(t[i]);
        a.pb(t[i]);
    }
    FOR(i,M)
    visit[i]=0;
     sort(t,t+n);
        FOR(i,n)
        {
            a[i]=lower_bound(t,t+n,a[i])-t+1;
        }
    for(i=n-1;i>=0;i--)
    {
      //   cout << a[i] << " ";
         pi[i]=query(M-1,visit)-query(a[i],visit);
         update(a[i],1,visit,M);
     }
    sort(pi,pi+n);
    for(i=n-1;i>=0;i--)
    {
     //   cout << i << " " << pi[i] << " " << k-pi[i]  << "\n";
        j=lower_bound(pi,pi+n,k-pi[i])-pi;
      //  cout << j << "\n";
        if(j!=n && j<i)
        ans+=i-j;
    }
    printf("%d",ans);
    return 0;
}