#include<bits/stdc++.h>

using namespace std;

string s;

int n;

map<char,int> mp;

int main()

{

    ios::sync_with_stdio();

    cin >> s >> n;

    int cnt = ;

    for(int i = ;i < s.length();i++)

    {

        if(mp[s[i]] == )   cnt++;

        mp[s[i]] = ;

    }

    if(s.length() < n)    cout << "impossible" << endl;

    else cout << max(,n-cnt) << endl;

    return ;

}

#include<bits/stdc++.h>

using namespace std;

int n,m,a[][];

long long c(int x)

{

    long long ans = ;

    for(int i = ;i <= x;i++)   ans *= ;

    return ans-;

}

int main()

{

    ios::sync_with_stdio();

    cin >> n >>m;

    for(int i = ;i <= n;i++)

    {

        for(int j = ;j <= m;j++)   cin >> a[i][j];

    }

    long long ans = -n*m;

    for(int i = ;i <= n;i++)

    {

        int cnt = ;

        for(int j = ;j <= m;j++)

        {

            if(a[i][j] == )    cnt++;

        }

        ans += c(cnt);

        ans += c(m-cnt);

    }

    for(int i = ;i <= m;i++)

    {

        int cnt = ;

        for(int j = ;j <= n;j++)

        {

            if(a[j][i] == )    cnt++;

        }

        ans += c(cnt);

        ans += c(n-cnt);

    }

    cout << ans << endl;

    return ;

}

#include<bits/stdc++.h>

using namespace std;

int n,a[],b[],cnt,vis[] = {};

vector<int> v[],ans[];

map<int,int> mp;

void dfs(int x)

{

    vis[x] = ;

    ans[cnt].push_back(x);

    for(int i = ;i < v[x].size();i++)

    {

        int t = v[x][i];

        if(vis[t])  continue;

        dfs(t);

    }

}

int main()

{

    ios::sync_with_stdio();

    cin >> n;

    for(int i = ;i <= n;i++)   cin >> a[i],b[i] = a[i];

    sort(b+,b++n);

    for(int i = ;i <= n;i++)   mp[b[i]] = i;

    for(int i = ;i <= n;i++)

    {

        v[i].push_back(mp[a[i]]);

    }

    cnt = ;

    for(int i = ;i <= n;i++)

    {

        if(!vis[i])

        {

            cnt++;

            dfs(i);

        }

    }

    cout << cnt << endl;

    for(int i = ;i <= cnt;i++) sort(ans[i].begin(),ans[i].end());

    for(int i = ;i <= cnt;i++)

    {

        cout << ans[i].size() << " ";

        for(int j = ;j < ans[i].size();j++)    cout << ans[i][j] << " ";

        cout << endl;

    }

    return ;

}

#include<bits/stdc++.h>

using namespace std;

int n,now,x;

map<int,int> mp;

int main()

{

    ios::sync_with_stdio();

    srand(time());

    cin >> n >> now >> x;

    cout << "? " << now << endl;

    int ne;

    cin >> now >> ne;

    if(now >= x)

    {

        cout << "! " << now << endl;

        return ;

    }

    for(int i = ;i <= ;i++)

    {

        long long t = (long long)rand()*rand()%n+;

        cout << "? " << t << endl;

        int v,vv;

        cin >> v >> vv;

        if(v < x && v > now)

        {

            now = v;

            ne = vv;

        }

    }

    while(ne != -)

    {

        cout << "? " << ne << endl;

        cin >> now >> ne;

        if(now >= x)

        {

            cout << "! " << now << endl;

            return ;

        }

    }

    cout << "! -1" << endl;

    return ;

}