#include <bits/stdc++.h> using namespace std; const int INF = 1e9; int n, k; string s; vector<int> J, O, I; int Bsearch(int idx, vector<int>& v) { int l = 0, r = v.size() - 1; int result = -1; while(l <= r) { int mid = (l + r) / 2; if(v[mid] > idx) { result = mid; r = mid - 1; } else { l = mid + 1; } } return result; } int main() { cin.tie(NULL)->sync_with_stdio(false); cin >> n >> k >> s; for(int i=0;i<s.size();i++) { if(s[i] == 'J') J.push_back(i); if(s[i] == 'O') O.push_back(i); if(s[i] == 'I') I.push_back(i); } // for(int i=0;i<n;i++) cout << i; cout << '\n'; int res = INF; for(int i = k-1; i < J.size(); i++) { int end_J = i; int start_J = i - k + 1; int start_O = Bsearch(J[end_J], O); if(start_O == -1 || start_O + k - 1 >= O.size()) continue; int end_O = start_O + k - 1; int start_I = Bsearch(O[end_O], I); if(start_I == -1 || start_I + k - 1 >= I.size()) continue; int end_I = start_I + k - 1; int sum = (I[end_I] - J[start_J] + 1) - (3 * k); res = min(res, sum); } cout << (res == INF ? -1 : res); return 0; }