// 중앙값

#include <iostream>
#include <cstring>
#include <unordered_map>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <vector>
#include <stack>
#include <queue>
#include <functional>
#include <list>
#include <deque>
#include <numeric>
#include <set>
#include <climits>
#include <utility>
#include <map>
#include <algorithm>
#define INF 987654321
#define MOD 1000000007
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
inline int max( int x, int y ){ return x > y ? x : y ; }
inline int min( int x, int y ){ return x < y ? x : y ; }
inline ll max( ll x, ll y ){ return x > y ? x : y ; }
inline ll min( ll x, ll y ){ return x < y ? x : y ; }
inline ull max( ull x, ull y ){ return x > y ? x : y ; }
inline ull min( ull x, ull y ){ return x < y ? x : y ; }
int gcd( int a, int b ) { return b ? gcd( b , a%b ) : a; }

int N, K;
int arr[250000+1], Tree[65536+1];
ll ansValue = 0;

void update( int index, int diff ){

	while( index <= 65536 ){
		Tree[index] += diff;
		index += ( index & -index );
	}
}

ll sum( int index ){

	ll ans = 0;
	while( index > 0 ){
		ans += Tree[index];
		index -= ( index & -index );
	}

	return ans;
}

int Calc(){

	int front = 0;
	int back = 65536;
	int mid, target = (K+1) >> 1;

	while( front < back ){
		mid = ( front + back ) >> 1;
		if( sum(mid+1) < target ){
			front = mid+1;
		}else{
			back = mid;
		}
	}

	return front;
}

int main() {

	scanf("%d %d", &N, &K);
	memset( arr, 0, sizeof(arr) );
	memset( Tree, 0, sizeof(Tree) );
	for( int i=1; i<=N; ++i ){
		scanf("%d", &arr[i]);
	}

	for( int i=1; i<=K; ++i ){
		update( arr[i]+1, 1 );
	}
	ansValue += Calc();
	for( int i=1; i<=N-K; ++i ){
		update( arr[i]+1, -1 );
		update( arr[i+K]+1, 1 );
		ansValue += Calc();
	}
	printf("%lld", ansValue);
    return 0;
}