#include <bits/stdc++.h> using namespace std; #define __Master_Moon__ int main() #define ll long long #define el "\n" #define base 300 #define fi first #define sq(x) (x)*(x) #define se second #define pub push_back #define puf push_front #define pii pair <int, int> #define pll pair <long long, long long> #define piii pair <long long, pair <int, int>> #define iiii pair <int, pair <int, pair <int, int>>> #define plll pair <long long, pair <long long, long long>> #define FOR(i, a, b) for(int i = (a);i <=(b);i++) #define FO(i, a, b) for(int i = (a);i >= (b);i--) #define REP(i, n) for(int i = 0;i < (n);i++) long const maxn = 2e5 + 5; int p[maxn][2],n,k,ans = INT_MAX; string s; void solve() { cin >> n >> k >> s; s = ' ' + s; int j = 1,cnt = 0; memset(p,-1,sizeof p); FOR(i,1,n) { if(s[i] == 'J') cnt++; while(cnt >= k) { if(s[j] == 'J') { cnt--; if(cnt < k) { cnt++; break; } } j++; } if(cnt >= k) p[i][0] = j; } j = 1; cnt = 0; FOR(i,1,n) { if(s[i] == 'O') cnt++; while(cnt >= k) { if(s[j] == 'O') { cnt--; if(cnt < k) { cnt++; break; } } j++; } if(cnt >= k && p[j-1][0] != -1) p[i][1] = p[j-1][0]; } j = 1; cnt = 0; FOR(i,1,n) { if(s[i] == 'I') cnt++; while(cnt >= k) { if(s[j] == 'I') { cnt--; if(cnt < k) { cnt++; break; } } j++; } if(cnt >= k && p[j-1][1] != -1) ans = min(ans,i-p[j-1][1]-3*k+1); } if(ans == INT_MAX) ans = -1; cout << ans; } __Master_Moon__ { ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); solve(); return 0; }