#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pl = pair<ll,ll>;
using pii = pair<int,int>;
using tpl = tuple<int,int,int>;
#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
ll n, k; cin >> n >> k;
vector<ll> a(n + 1);
for (int i = 1; i <= n; i++) cin >> a[i];
ll sum = accumulate(all(a), 0LL), lim = sum / k;
if (sum % k || *max_element(all(a)) > lim) return cout << -1 << "\n", 0;
vector<pl> events; ll cur = 0;
for (int i = 1; i <= n; i++) {
if (cur + a[i] > lim) {
// place at [cur + 1..lim] of current row and [1..cur + a[i] - lim] of next row
events.emplace_back(cur + 1, i);
events.emplace_back(lim, -i);
events.emplace_back(1, i);
events.emplace_back(cur + a[i] - lim, -i);
cur += a[i] - lim;
}
else {
// place at [cur + 1..cur + a[i]] of current row
events.emplace_back(cur + 1, i);
events.emplace_back(cur + a[i], -i);
cur += a[i];
}
}
sort(all(events));
set<int> active;
ll last = 0;
for (int i = 0; i < events.size();) {
ll p = events[i].first;
vector<int> toErase;
for (; i < events.size() && events[i].first == p; i++) {
int idx = events[i].second;
if (idx > 0) active.insert(idx);
else toErase.push_back(-idx);
}
if (toErase.empty()) continue;
cout << p - last << " ";
for (int u : active) cout << u << " ";
cout << "\n";
for (int u : toErase) active.erase(u);
last = p;
}
return 0;
}
