#include <bits//stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset; #define ll long long #define ld long double #define iloop(m, h) for (auto i = m; i != h; i += (m < h ? 1 : -1)) #define jloop(m, h) for (auto j = m; j != h; j += (m < h ? 1 : -1)) #define kloop(m, h) for (auto k = m; k != h; k += (m < h ? 1 : -1)) #define lloop(m, h) for (auto l = m; l != h; l += (m < h ? 1 : -1)) #define iloop_(m, h, g) for (auto i = m; i < h; i += g) #define jloop_(m, h, g) for (auto j = m; j < h; j += g) #define kloop_(m, h, g) for (auto k = m; k < h; k += g) #define lloop_(m, h, g) for (auto l = m; l < h; l += g) #define getchar_unlocked _getchar_nolock // comment before submission #define pll pair<ll, ll> #define plll pair<ll, pll> #define pllll pair<pll, pll> #define vll vector<ll> #define qll queue<ll> #define dll deque<ll> #define pqll priority_queue<ll> #define gll greater<ll> #define INF 1000000000000000 #define MOD1 1000000007 #define MOD2 998244353 #define MOD3 1000000009 mt19937 rng(chrono::system_clock::now().time_since_epoch().count()); int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); ll n, m; string s; cin >> n >> m >> s; ll j[n+1], o[n+1], i_[n+1]; j[0] = o[0] = i_[0] = 0; iloop(1, n+1) { j[i] = j[i-1]; o[i] = o[i-1]; i_[i] = i_[i-1]; if (s[i-1] == 'J') j[i]++; else if (s[i-1] == 'O') o[i]++; else i_[i]++; } ll cans = INF, nid; iloop(1, n+1) { //cout << i << " "; if (i_[i] >= m) { nid = lower_bound(i_, i_+n+1, i_[i]-m+1) - i_ - 1; //cout << nid << " "; if (o[nid] >= m) { nid = lower_bound(o, o+n+1, o[nid]-m+1) - o - 1; //cout << nid << " "; if (j[nid] >= m) { nid = lower_bound(j, j+n+1, j[nid]-m+1) - j - 1; cans = min(cans, i-nid - 3*m); //cout << nid << " "; } } } //cout << "\n"; } cout << (cans == INF ? -1 : cans); }