#include <iostream>
#include <string>
using namespace std ;
int val ;
bool once_used = false ;
int superDigit(string n, int k) {
    if (!once_used){
        string adder = n ;
        for (int i = 1 ; i < k; i++) {
            n+=adder;
        }
        once_used = true ;
    }
    if (n.size() == 1){return stoi(n);}
    else {
        int total = 0 ;
        for (int i = 0 ;i < n.size(); i++)  {
            total +=n[i] - '0';
        }
        n = to_string(total);
    val =  superDigit( n, k) ;
    cout << val;
    }
    ///cout << val ;
    return val ;
    //return total ;
}
int main() {
string n ;
cin >> n ;
int k ;
cin >> k ;
cout << superDigit(n, k);
}