#include <iostream>
    #include <vector>
    #include <map>
    #include <cmath>
    #include <algorithm>
    #define int long long
    using namespace std;
    signed main(){
        int n, k;
        cin>>n>>k;
        string a;
        cin>>a;
        map <int, int> c;
        for (int i=0; i<n; i++){
            c[a[i]-48]++;
        }
        vector <int> answer;
        for (int l=0; l<10; l++){
            if (c[l]>=k){
                answer.push_back(c[l]-k);
            }if (c[l]<k){
                vector <int> b(n);
                for (int i=0; i<n; i++){
                    b[i]=abs(a[i]-l-48);
                }
                sort(b.begin(), b.end());
                /*for (int i=0; i<n; i++){
                    cout<<b[i]<<" ";
                }
                */
                cout<<"\n";
                int sum=0;
                for (int i=0; i<k; i++){
                    sum+=b[i];
                }
                //cout<<sum<<"\n";
                answer.push_back(sum);
            }
        }
        int minimum=answer[0];
        for (int i=0; i<answer.size(); i++){
            if (answer[i]<minimum){
                minimum=answer[i];
            }
        }
        cout<<minimum<<endl;
    }