#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ll long long
#define all(x) (x).begin(), (x).end()
const int mxn = 1e6 + 2;
vector<int> v;
int L[mxn], R[mxn], indL[mxn], indR[mxn], suml[mxn], sumr[mxn];
struct S {
int ind;
};
bool operator < (S f, S s) {
return L[f.ind] + R[f.ind] < L[s.ind] + R[s.ind];
}
string s;
struct SGT {
vector<int> sumL, sumR, lzL, lzR;
SGT(int sz) {
sumL.resize(3 * sz);
sumR.resize(3 * sz);
lzL.resize(3 * sz);
lzR.resize(3 * sz);
}
void build(int k, int l, int r) {
if (l == r) {
sumL[k] = suml[l];
sumR[k] = sumr[l];
return;
}
int mid = (l + r) / 2;
build(k * 2, l, mid);
build(k * 2 + 1, mid + 1, r);
sumL[k] = max(sumL[k * 2], sumL[k * 2 + 1]);
sumR[k] = max(sumR[k * 2], sumR[k * 2 + 1]);
}
void push(int k, int l, int r) {
if (lzL[k]) {
sumL[k] -= lzL[k];
if (l != r) {
lzL[k * 2] += lzL[k];
lzL[k * 2 + 1] += lzL[k];
}
lzL[k] = 0;
}
if (lzR[k]) {
sumR[k] -= lzR[k];
if (l != r) {
lzR[k * 2] += lzR[k];
lzR[k * 2 + 1] += lzR[k];
}
lzR[k] = 0;
}
}
int getValL(int k, int l, int r, int i) {
push(k, l, r);
if (l > i || r < i) return 0;
int mid = (l + r) / 2;
if (l == r) return sumL[k];
return max(getValL(k * 2, l, mid, i), getValL(k * 2 + 1, mid + 1, r, i));
}
int getValR(int k, int l, int r, int i) {
push(k, l, r);
if (l > i || r < i) return 0;
int mid = (l + r) / 2;
if (l == r) return sumR[k];
return max(getValR(k * 2, l, mid, i), getValR(k * 2 + 1, mid + 1, r, i));
}
int getL(int k, int l, int r, int i, int val) {
push(k, l, r);
if (l > i || sumR[k] < val) return 0;
int mid = (l + r) / 2;
if (r <= i) {
if (l == r) return l;
push(k * 2 + 1, mid + 1, r);
if (sumR[k * 2 + 1] >= val) return getL(k * 2 + 1, mid + 1, r, i, val);
return getL(k * 2, l, mid, i, val);
}
return max(getL(k * 2, l, mid, i, val), getL(k * 2 + 1, mid + 1, r, i, val));
}
int getR(int k, int l, int r, int i, int val) {
push(k, l, r);
if (r < i || sumL[k] < val) return mxn;
int mid = (l + r) / 2;
if (l >= i) {
if (l == r) return l;
push(k * 2, l, mid);
if (sumL[k * 2] >= val) return getR(k * 2, l, mid, i, val);
return getR(k * 2 + 1, mid + 1, r, i, val);
}
return min(getR(k * 2, l, mid, i, val), getR(k * 2 + 1, mid + 1, r, i, val));
}
void fill(int k, int l, int r, int i, int j) {
push(k, l, r);
if ((sumL[k] <= 0 && sumR[k] <= 0) || l > j || r < i) return;
int mid = (l + r) / 2;
if (i <= l && r <= j) {
sumL[k] = sumR[k] = 0;
if (l == r) {
if (s[l] == 'b') v.push_back(l);
return;
}
fill(k * 2, l, mid, i, j);
fill(k * 2 + 1, mid + 1, r, i, j);
}
fill(k * 2, l, mid, i, j);
fill(k * 2 + 1, mid + 1, r, i, j);
sumL[k] = max(sumL[k * 2], sumL[k * 2 + 1]);
sumR[k] = max(sumR[k * 2], sumR[k * 2 + 1]);
}
void updL(int k, int l, int r, int i, int v) {
push(k, l, r);
if (r < i) return;
int mid = (l + r) / 2;
if (l >= i) {
lzL[k] += v;
push(k, l, r);
return;
}
updL(k * 2, l, mid, i, v);
updL(k * 2 + 1, mid + 1, r, i, v);
sumL[k] = max(sumL[k * 2], sumL[k * 2 + 1]);
}
void updR(int k, int l, int r, int i, int v) {
push(k, l, r);
if (l > i) return;
int mid = (l + r) / 2;
if (r <= i) {
lzR[k] += v;
push(k, l, r);
return;
}
updR(k * 2, l, mid, i, v);
updR(k * 2 + 1, mid + 1, r, i, v);
sumR[k] = max(sumR[k * 2], sumR[k * 2 + 1]);
}
} sgt(mxn);
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, k;
cin >> n >> k;
cin >> s;
s = "." + s;
int sum = 0;
vector<int> pos;
for (int i = 1; i <= n; i++) {
sum += (s[i] == 'b');
suml[i] = sum;
}
sum = 0;
for (int i = n; i >= 1; i--) {
sum += (s[i] == 'b');
sumr[i] = sum;
}
sum = 0;
for (int i = 1; i <= n; i++) {
if (s[i] == 'b') sum++;
else {
L[i] = sum;
if (pos.size()) R[pos.back()] = sum;
pos.push_back(i);
sum = 0;
}
}
R[pos.back()] = sum;
priority_queue<S> pq;
for (int i = 0; i < pos.size(); i++) {
indL[pos[i]] = (i > 0 ? pos[i - 1] : -1);
indR[pos[i]] = (i < pos.size() - 1 ? pos[i + 1] : -1);
pq.push({pos[i]});
}
sgt.build(1, 1, n);
vector<vector<int>> ans;
while (pq.size()) {
int ind = pq.top().ind;
int lt = indL[ind], rt = indR[ind];
pq.pop();
int val = sgt.getValR(1, 1, n, ind);
int posL = sgt.getL(1, 1, n, ind, min(L[ind], k) + val);
val = sgt.getValL(1, 1, n, posL - 1);
int posR = sgt.getR(1, 1, n, posL, k + val);
v = {ind};
sgt.fill(1, 1, n, posL, posR);
sgt.updL(1, 1, n, posR, k);
sgt.updR(1, 1, n, posL, k);
sort(all(v));
ans.push_back(v);
if (1 <= lt && lt <= n) R[lt] = L[ind] + R[ind] - k, indR[lt] = rt;
if (1 <= rt && rt <= n) L[rt] = L[ind] + R[ind] - k, indL[rt] = lt;
}
for (int i = ans.size() - 1; i >= 0; i--) {
for (auto x : ans[i]) cout << x << " ";
cout << endl;
}
}
