#include <bits/stdc++.h> #define int long long int n,k; std::vector<int> Jidx; std::vector<int> Oidx; std::vector<int> Iidx; signed main() { std::ios::sync_with_stdio(false);std::cin.tie(nullptr); std::cin >> n >> k; std::string str; std::cin >> str; for(int i=0;i<n;i++){ if(str[i]=='J')Jidx.push_back(i); if(str[i]=='O')Oidx.push_back(i); if(str[i]=='I')Iidx.push_back(i); } int best = 1e18; for(int i=0;i<=Jidx.size()-k;i++){ //std::cout << Jidx[i] << ' ' << Jidx[i+k-1]<< ' '; int cost = Jidx[i+k-1]-Jidx[i]+1-k; int Os = std::upper_bound(Oidx.begin(),Oidx.end(),Jidx[i+k-1])-Oidx.begin(); if(Os+k-1>=Oidx.size())continue; //std::cout << Oidx[i] << ' ' << Oidx[i+k-1]<< ' '; cost+=Oidx[Os]-Jidx[i+k-1]-1; cost+=Oidx[Os+k-1]-Oidx[Os]+1-k; int Is = std::upper_bound(Iidx.begin(),Iidx.end(),Oidx[Os+k-1])-Iidx.begin(); if(Is+k-1>=Iidx.size())continue; //std::cout << Iidx[i] << ' ' << Iidx[i+k-1]<< ':'; cost+=Iidx[Is]-Oidx[Os+k-1]-1; cost+=Iidx[Is+k-1]-Iidx[Is]+1-k; best=std::min(best,cost); //std::cout << cost << '\n'; } if(best==1e18)best=-1; std::cout << best << '\n'; }