#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <set>
#include <vector>
#include <array>
using namespace std;
typedef long long ll;
const int maxn=1e6+5;
ll a[maxn];
ll sum;
vector < array < ll, 3 > > v;
set < int > cur;
vector < vector < int > > sol;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, k;
cin >> n >> k;
for(int i=0; i<n; i++){
cin >> a[i];
sum+=a[i];
}
if(sum%k){
cout << -1 << '\n';
return 0;
}
sum/=k;
for(int i=0; i<n; i++){
if(a[i]>sum){
cout << -1 << '\n';
return 0;
}
}
int pos=0;
int iduc;
for(int i=0; i<n; i++){
iduc=pos+a[i];
if(iduc>sum){
v.push_back({pos, i+1, 1});
v.push_back({sum, i+1, 0});
iduc-=sum;
pos=0;
}
v.push_back({pos, i+1, 1});
v.push_back({iduc, i+1, 0});
if(iduc==sum){
iduc=0;
}
pos=iduc;
}
sort(v.begin(), v.end());
vector < int > vi;
for(int i=0; i<(int)v.size(); i++){
if(v[i][2]==1){
cur.insert(v[i][1]);
}
else{
cur.erase(v[i][1]);
}
if(i==(int)v.size()-1 || v[i][0]==v[i+1][0]){
continue;
}
vi.push_back(v[i+1][0]-v[i][0]);
for(set < int >::iterator it=cur.begin(); it!=cur.end(); it++){
vi.push_back(*it);
}
sol.push_back(vi);
vi.clear();
}
cout << sol.size() << '\n';
for(int i=0; i<(int)sol.size(); i++){
for(int j=0; j<k+1; j++){
cout << sol[i][j] << ' ';
}
cout << '\n';
}
return 0;
}
