where is my mistake?

#include <cstdio>
#include <cmath>

inline int lb(int n) { return ceil(log(double(n))/log(2.0)); }

int main() {
    int n,k;
    scanf("%d%d",&n,&k);
    if (n<=k) printf("%d",lb(n));
    else {
        int ans=lb(k);
        n-=1l << ans;
        ans+=n/k;
        if (n%k) ++ans;
        printf("%d",ans);
    }
}