#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair <int, int>
#define X first
#define Y second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
cout << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
for (; l != r; ++l) cout << *l << " \n"[l + 1 == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
return o >> a.X >> a.Y;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
return o << '(' << a.X << ", " << a.Y << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
bool is = false;
if (a.empty()) return o << "{}";
for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
return o << '}';
}
template <typename T> struct vv : vector <vector <T>> {
vv(int n, int m, T v) : vector <vector <T>> (n, vector <T>(m, v)) {}
vv() {}
};
template <typename T> struct vvv : vector <vv <T>> {
vvv(int n, int m, int k, T v) : vector <vv <T>> (n, vv <T>(m, k, v)) {}
vvv() {}
};
#ifdef Doludu
#define test(args...) abc("[" + string(#args) + "]", args)
#define owo freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#else
#define test(args...) void(0)
#define owo ios::sync_with_stdio(false); cin.tie(0)
#endif
const int mod = 1e9 + 7, N = 200000, logN = 20, K = 48763;
int main () {
owo;
int n, k;
cin >> n >> k;
vector <int> a(n);
vector <lli> pre = {0};
for (int i = 0; i < n; ++i)
cin >> a[i], pre.pb(pre.back() + a[i]);
if (pre.back() % k) {
cout << -1 << endl;
return 0;
}
lli len = pre.back() / k;
for (int i : a)
if (len < i) {
cout << -1 << endl;
return 0;
}
vector <lli> split;
for (lli &i : pre)
i %= len, split.pb(i);
sort(all(split));
split.resize(unique(all(split)) - split.begin());
split.pb(len);
int m = split.size();
vector <vector <int>> ans(m);
for (int i = 0; i < n; ++i) {
int from = lower_bound(all(split), pre[i]) - split.begin();
int to = lower_bound(all(split), pre[i + 1]) - split.begin();
for (int j = (from + 1) % m; ; j = (j + 1) % m) {
ans[j].pb(i + 1);
if (j == to)
break;
}
}
cout << m - 1 << endl;
for (int i = 1; i < m; ++i) {
cout << split[i] - split[i - 1] << ' ';
printv(all(ans[i]));
}
}
