#include<iostream>
#include<cstdio>
#include<algorithm>

using namespace std;

int main()
{
    int a,b;
    while(cin>>a>>b,b!=0)
    {
        int g=__gcd(a,b);
        a/=g; b/=g;
	    while(b%2==0)
	        b/=2;
	    while(b%5==0)
	        b/=5;
        if(b==1)
        {
            cout<<1<<endl;
            continue;
        }
        long long nine=9;
        for(int i=1;;i++)
        {
            if(nine%b==0)
            {
                cout<<i<<endl;
                break;
            }
            nine=nine%b*10+9;
        } 
    }
}