#include<iostream>
using namespace std;
int main(){
	int n,k,a[2005],c=0;
	cin>>n>>k;
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int i=1;i<=n;i++)
		for(int j=i+k;j<=n;j++)
			if(a[i]==a[j])
				cout<<i<<" "<<j<<"\n",c++;
	cout<<c;
}