#include <bits/stdc++.h>
#define ll long long
using namespace std;
 
const int oo = 1e9 + 7;
const int N = 1e3 + 5;

int n, k;
int a[N];

int main() {
	cin >> n >> k;
	int maxx = 0, minn = oo;
	for (int i = 1; i <= n; ++i) {
		cin >> a[i];
		maxx = max(maxx, a[i]);
		minn = min(minn, a[i]);
	}
	
	sort(a + 1, a + n + 1);
	
	int ans = 0;
	int X = (maxx - minn) / (k - 1);
	for (int d = 1; d <= X; ++d) {
		for (int i = 1; i <= n; ++i) {
			for (int j = i; j <= n; ++j) {
				if (a[j] - a[i] == d) {
					ans += (n - 2);
					cout << i << ' ' << j << '\n';
					break;
				}
			}
		}
	}

	cout << ans;
	
    return 0;

}