#include<bits/stdc++.h>

typedef long long ll;
int main()
{
    int task;
    scanf("%d",&task);
    while(task--)
    {
        ll n,d;
        scanf("%lld%lld",&n,&d);
        ll mul=1;
        for(ll m=0;;++m)
        {

            if(mul>=n)
            {
                printf("%lld\n",m);
                break;
            }
            mul*=d+1;
        }
    }
    return 0;
}