#include <bits/stdc++.h>
using ll = long long;
using std::vector;
using std::array;
using std::pair;
using std::tuple;
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int N, K;
std::cin >> N >> K;
vector<ll> A(N);
for (auto& x : A) {
std::cin >> x;
}
const ll sum = std::accumulate(A.begin(), A.end(), 0ll);
const ll max = *std::max_element(A.begin(), A.end());
const ll turn = sum / K;
if (sum % K != 0 or max > turn) {
std::cout << "-1\n";
return 0;
}
ll cur = 0;
vector<vector<pair<ll, int>>> list = {{}};
vector<ll> split = {0, turn};
split.reserve(N + 2);
for (int i = 0; i < N; ++i) {
cur += A[i];
if (cur >= turn) {
cur -= turn;
list.back().emplace_back(turn, i);
list.emplace_back();
}
list.back().emplace_back(cur, i);
split.push_back(cur);
}
std::sort(split.begin(), split.end());
split.erase(std::unique(split.begin(), split.end()), split.end());
const int Q = (int)split.size() - 1;
std::cout << Q << '\n';
for (int i = 0; i < Q; ++i) {
std::cout << split[i + 1] - split[i];
for (int j = 0; j < K; ++j) {
std::cout << ' ' << std::lower_bound(list[j].begin(), list[j].end(), pair(split[i] + 1, 0))->second + 1;
}
std::cout << '\n';
}
return 0;
}
