#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
int in() {
  int x;
  cin >> x;
  return x;
}
long long lin() {
  long long x;
  cin >> x;
  return x;
}
string stin() {
  string s;
  cin >> s;
  return s;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
vector<int> iota(int n) {
  vector<int> a(n);
  iota(begin(a), end(a), 0);
  return a;
}
void print() { putchar(' '); }
void print(bool a) { cout << a; }
void print(int a) { cout << a; }
void print(long long a) { cout << a; }
void print(char a) { cout << a; }
void print(string& a) { cout << a; }
void print(double a) { cout << a; }
template <class T>
void print(const vector<T>&);
template <class T, size_t size>
void print(const array<T, size>&);
template <class T, class L>
void print(const pair<T, L>& p);
template <class T, size_t size>
void print(const T (&)[size]);
template <class T>
void print(const vector<T>& a) {
  if (a.empty()) return;
  print(a[0]);
  for (auto i = a.begin(); ++i != a.end();) {
    cout << " ";
    print(*i);
  }
  cout << endl;
}
template <class T>
void print(const deque<T>& a) {
  if (a.empty()) return;
  print(a[0]);
  for (auto i = a.begin(); ++i != a.end();) {
    cout << " ";
    print(*i);
  }
}
template <class T, size_t size>
void print(const array<T, size>& a) {
  print(a[0]);
  for (auto i = a.begin(); ++i != a.end();) {
    cout << " ";
    print(*i);
  }
}
template <class T, class L>
void print(const pair<T, L>& p) {
  cout << '(';
  print(p.first);
  cout << ",";
  print(p.second);
  cout << ')';
}
template <class T, size_t size>
void print(const T (&a)[size]) {
  print(a[0]);
  for (auto i = a; ++i != end(a);) {
    cout << " ";
    print(*i);
  }
}
template <class T>
void print(const T& a) {
  cout << a;
}
int out() {
  putchar('\n');
  return 0;
}
template <class T>
int out(const T& t) {
  print(t);
  putchar('\n');
  return 0;
}
template <class Head, class... Tail>
int out(const Head& head, const Tail&... tail) {
  print(head);
  putchar(' ');
  out(tail...);
  return 0;
}
long long gcd(long long a, long long b) {
  while (b) {
    long long c = b;
    b = a % b;
    a = c;
  }
  return a;
}
long long lcm(long long a, long long b) {
  if (!a || !b) return 0;
  return a * b / gcd(a, b);
}
const int INF = 1061109567;
const long long LINF = 4557430888798830399LL;
template <class... T>
void err(const T&...) {}
int n, k, cnt, white, black, l;
char tmp;
int loc[3001];
long long maxm, minm, max, diff, amount;
signed main() {
  n = in(), k = in();
  for (long long i = 0; i < n; i++) {
    cin >> tmp;
    if (tmp == 'R') {
      white++;
      if (black > 0) black--;
    } else {
      loc[++cnt] = i + 1;
      maxm += white;
      minm = white + black;
      black++;
    }
  }
  vector<int> v;
  if (k >= minm && k <= maxm) {
    diff = maxm - k;
    for (long long j = 0; j < k; j++) {
      amount = 0;
      l = 1;
      v.clear();
      while (l <= cnt) {
        int d = loc[l] - l;
        if (d > 0) {
          int x = loc[l] - 1;
          v.push_back(x);
          loc[l] = x;
          amount++;
          if (diff == 0) break;
          if (amount > 1) diff--;
          if (diff == 0) break;
          l++;
          while (l <= cnt && ((loc[l] - l) == d)) {
            l++;
          }
        } else {
          l++;
        }
      }
      cout << amount << ' ';
      print(v);
      if (diff == 0) break;
    }
    int g;
    l = 1;
    while (l <= cnt) {
      g = loc[l];
      while (g > l) {
        cout << "1 " << g - 1 << '\n';
        g--;
      }
      l++;
    }
  } else {
    out(-1);
  }
}
