#include<bits/stdc++.h>

using namespace std;

#define LL long long

const int N = 1e6 + 10;

const int INF = 0x3f3f3f3f;

int a[N];
int main()
{
	int n,k;
	cin >> n >> k;
	for(int i = 1;i<=n;i++)
		cin >> a[i];
	int sum = 0;
	for(int i = 1;i<=n;i++)
	
		for(int j = i+k;j<=n;j++)
		{
			if(a[i]==a[j])
			{
				sum++;
				cout << i << " " << j << endl;
			}
		}
	cout << sum << endl;
	return 0;
}