#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>

char str[2010]; int len;
char construct[2010];
int n;
int ans;
std::vector<char> alphabet;

void Work() {
    int sum = 0;
    for (int st = 1; st <= n; ++st) {
        int maxprefix = 0;
        for (int delta = 0; st + delta <= n && 1 + delta <= len && str[1 + delta] == construct[st + delta]; ++delta, ++maxprefix);
        sum += maxprefix;
    }
    ans = std::max(ans, sum);
}

void dfs(int now) {
    if (now > n) {
        Work();
        return ;
    }
    for (char i : alphabet) {
        construct[now] = i;
        dfs(now + 1);
    }
}

int main() {
    freopen("string.in", "r", stdin);
    freopen("string.out", "w", stdout);
    scanf("%s", str + 1);
    scanf("%d", &n);
    
    len = strlen(str + 1);
    for (int i = 1; i <= len; ++i) {
        alphabet.push_back(str[i]);
    }
    std::sort(alphabet.begin(), alphabet.end());
    alphabet.erase(std::unique(alphabet.begin(), alphabet.end()), alphabet.end());
    
    dfs(1);
    
    printf("%d\n", ans);
    return 0;
}