#include <bits/stdc++.h>
using namespace std;
int n, k, tot, len[(int)(3e3 + 4)];
pair<int, int> bound[(int)(3e3 + 4)];
string s;
vector<int> poz, ans[3000004];
void fail();
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> k;
  cin >> s;
  for (int i = s.size() - 1; i >= 0; --i)
    if (s[i] == 'R') {
      len[poz.size()] = (s.size() - poz.size()) - i - 1;
      tot += len[poz.size()];
      poz.push_back(i);
    }
  if (k > tot) fail();
  int p = 0;
  while (p < poz.size() && !len[p]) ++p;
  bound[p] = {1, len[p]};
  tot -= len[p];
  for (int i = p + 1; i < poz.size(); ++i) {
    int l, r, dist, ramas;
    dist = dist = poz[i - 1] - poz[i] - 1;
    l = max(1, bound[i - 1].first + 1 - dist);
    tot -= len[i];
    if (k - tot - len[i] + 1 >= l)
      bound[i] = {k - tot - len[i] + 1, k - tot};
    else if (l + len[i] - 1 <= k)
      bound[i] = {l, l + len[i] - 1};
    else
      fail();
  }
  for (int i = 0; i < poz.size(); ++i) {
    int p = poz[i];
    while (bound[i].first <= bound[i].second) {
      ans[bound[i].first].push_back(p + 1);
      ++p;
      ++bound[i].first;
    }
  }
  for (int i = 1; i < k + 1; ++i) {
    printf("%d ", ans[i].size());
    for (auto it : ans[i]) printf("%d ", it);
    printf("\n");
  }
  return 0;
}
void fail() {
  cout << -1;
  exit(0);
}
