#include "iostream"

 #include "cstdio"

 #include "cstring"

 #include "string"

 using namespace std;

 const int maxn=+;

 int vis[maxn],n;

 string s;

 int main()

 {

     cin>>s;

     cin>>n;

     int len=s.length();

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

         vis[s[i]-'a']++;

     }

     if(len<n){

         cout<<"impossible"<<endl;

     }else{

         int num=;

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

             if(vis[i])

                 num++;

         }

         if(num>=n)

             cout<<""<<endl;

         else

             cout<<(n-num)<<endl;

     }

     return ;

 }

 #include "iostream"

 #include "cstdio"

 #include "cstring"

 #include "string"

 #include "vector"

 #include "cmath"

 using namespace std;

 const int maxn=+;

 int n,m;

 int a[maxn][maxn];

 struct Node

 {

     int zero,one;

 };

 vector<Node>p;

 int main()

 {

     cin>>n>>m;

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

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

             cin>>a[i][j];

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

         int num0=,num1=;

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

             if(a[i][j]==)

                 num1++;

             else

                 num0++;

         }

         Node e;

         e.zero=num0,e.one=num1;

         p.push_back(e);

     }

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

         int num0=,num1=;

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

             if(a[i][j]==)

                 num1++;

             else

                 num0++;

         }

         Node r;

         r.zero=num0,r.one=num1;

         p.push_back(r);

     }

     long long res=;

     for(int i=;i<p.size();i++){

         res+=(long long)pow(,p[i].zero)-(long long);

         res+=(long long)pow(,p[i].one)-(long long);

     }

     res-=(n*m);

     cout<<res<<endl;

     return ;

 }