#include<stdio.h>
int main()
{
int n,a,b;
scanf("%d",&n);
while(n--)
{
scanf("%d%d",&a,&b);
int sum =0 ;
while(a != 0)
{
sum += a/b;
a /= b;
}
printf("%d\n",sum);
}
return 0;
int main()
{
int n,a,b;
scanf("%d",&n);
while(n--)
{
scanf("%d%d",&a,&b);
int sum =0 ;
while(a != 0)
{
sum += a/b;
a /= b;
}
printf("%d\n",sum);
}
return 0;
}