#include <bits/stdc++.h>
#define y1 theboatman
#define make_struct(args...) {args}
#define int long long
using namespace std;
void sub_task2(int n, int k, vector <int> &a) {
set <pair <int, int> > s;
for(int i = 0; i < n; i++) {
s.insert(make_pair(-a[i], i));
}
vector <vector <int> > ans;
while(s.size()) {
auto it = *s.begin();
s.erase(it);
if (!s.size()) {
cout << "-1\n";
exit(0);
}
auto it1 = *s.begin();
s.erase(it1);
vector <int> way;
way.push_back(-it1.first);
way.push_back(it.second + 1);
way.push_back(it1.second + 1);
ans.push_back(way);
if (it.first - it1.first < 0) {
s.insert(make_pair(it.first - it1.first, it.second));
}
}
cout << ans.size() << "\n";
for(auto it : ans) {
for(auto i : it) {
cout << i << " ";
}
cout << "\n";
}
}
int32_t main() {
cin.tie(0);
ios :: sync_with_stdio(0);
int n, k;
cin >> n >> k;
vector <int> a(n);
for(int i = 0; i < n; i++) {
cin >> a[i];
}
if (k == 2) {
sub_task2(n, k, a);
}
else {
cout << "kek\n";
}
return 0;
}
/*
2 3 3 4 6
*/
