#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define ins insert
#define pq priority_queue
#define minele min_element
#define maxele max_element
#define lb lower_bound //first pos >= val
#define ub upper_bound // first pos > val
#define cnt_bit __builtin_popcount
#define debug(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma")
using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;


int d4x[4] = {1, 0, -1, 0}; int d4y[4] = {0, 1, 0, -1};
int d8x[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int d8y[8] = {1, 1, 0, -1, -1, -1, 0, 1};

const ll oo = 1e18;
const ll maxN = 1e6;

/* Author : Le Ngoc Bao Anh, 10A5, LQD High School for Gifted Student */

void maximize(int &a, int b) {
    a = max(a, b);
}

void minimize(int &a, int b) {
    a = min(a, b);
}

int pref[maxN][30];

void solve() {
    string s; cin >> s;
    int n = s.size(); s = "#" + s;
    int k; cin >> k;

    int ans = min(k, n);
    for(int i = 1; i <= n; i++) {
        int x = (s[i] - 'a' + 1);
        for(int j = 1; j <= 26; j++) pref[i][j] = pref[i - 1][j];
        pref[i][x]++;
    }

    for(int i = 1; i <= n; i++) {
        int L = i, R = n;
        while(L <= R) {
            int mid = (L + R) >> 1;
            bool ok = false;
            for(int j = 1; j <= 26; j++) {
                int x = (pref[mid][j] - pref[i - 1][j]);
                if(x + k >= mid - i + 1) {
                    ok = true;
                }
            }

            if(ok) {
                ans = max(ans, mid - i + 1);
                L = mid + 1;
            } else R = mid - 1;
        }
    }

    cout << ans;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #else
    //online
    #endif

    int tc = 1, ddd = 0;
    // cin >> tc;
    while(tc--) {
        //ddd++;
        //cout << "Case #" << ddd << ": ";
        solve();
    }
}