I can't find mistake, help!!


#include <iostream>
#include <cmath>
using namespace std;
int main() {
    __int64 n,k;
    int s = 0;
    cin>>n>>k;
    int step;
    step = log(k)/log(2);
    if(n-pow(2,step+1)>=0) {
        n -= pow(2,step+1);
        s = (step+1)+ceil(n*1./k);
    } else {
        s = ceil(log(n)/log(2));
    }
    cout<<s;
}