#include<bits/stdc++.h>
#define ll long long
#define N 2001
using namespace std;
ll n,ans,cnt;
string s;
char a[27];
map<char,bool> mp;
void dfs(ll dep,string ss){
    if(dep>n){
        ll res=0,now;
        for(int i=0;i<n;i++){
            now=0;
            for(int j=0;j<s.size();j++){
                if(ss[i+j]!=s[j]) break;
                now++;
            }
            res+=now;
        }
        ans=max(ans,res);
        return ;
    }
    for(int i=1;i<=cnt;i++) dfs(dep+1,ss+a[i]);
    return ;
}
int main(){
    freopen("string.in","r",stdin);
    freopen("string.out","w",stdout);
    cin>>s>>n;
    for(int i=0;i<s.size();i++)
    if(!mp[s[i]]){
        mp[s[i]]=true;
        a[++cnt]=s[i];
    }
    dfs(1,"");
    cout<<ans<<endl;
    return 0;
}