#include <bits/stdc++.h>
using namespace std;
using T = array<int, 2>;
class comp{
public:
bool operator()(const T &x, const T &y) {
return x[0] < y[0];
}
};
const int Z = 1e6+1, oo = 2e9;
int N, A[Z], S[Z], P[Z];
array<int, 2> DP[Z];
const T ID = {-oo, -1};
void build(int x) {
priority_queue<array<int, 2>, vector<T>, comp> b;
int r = 0;
b.push(DP[0]);
for(int i = 1; i <= N; i++) {
int R = max(-1, i - A[S[i]]);
while(r < R) b.push(DP[++r]);
r = R;
while(!empty(b) && (b.top()[1] < i - x || b.top()[1] > R)) b.pop();
if(empty(b)) {
DP[i] = ID;
} else {
DP[i] = b.top();
P[i] = DP[i][1];
DP[i][1] = i;
++DP[i][0];
}
}
}
int main() {
ios::sync_with_stdio(0), cin.tie(0);
cin >> N;
for(int i = 1; i <= N; i++) {
cin >> A[i];
S[i] = i;
}
fill(DP, DP+Z, ID);
DP[0] = {};
sort(S, S + N + 1, [&](int i, int j) {
return A[i] < A[j];
});
build(1e6);
int best = DP[N][0], sz = N;
for(int j=1<<20; j/=2; ) {
if(sz - j < A[S[N]]) continue;
build(sz - j);
if(DP[N][0] == best) sz -= j;
}
build(sz);
int curr = P[N];
vector<vector<int>> res = {{}};
for(int i = N + 1; --i; ) {
if(curr == i) {
res.push_back({});
curr = P[curr];
}
res.back().push_back(S[i]);
}
cout << size(res) << '\n';
for(auto &V : res) {
cout << size(V);
for(auto &i : V) cout << ' ' << i;
cout << '\n';
}
}
