#include <iostream>

using namespace std;

int main()
{
    int a, b, n, s;
    
    while(cin >> a >> b >> n)
    {
        s = 0;
        
        while(a >= b)
        {
            a -= b;
        }
        
        for(int i = 0; i < n; i++)
        {
            a *= 10;
            
            while(a >= b)
            {
                a -= b;
                
                s++;
            }
        }
        
        cout << s << endl;
    }
    
    return 0;
}