Background

Cirno: I got it! The answer is $-1 \ 0$, because Gensokyo has no teleporter!

Rumia: I really can’t with you... Fine, let’s do another middle school math problem.

Saying that, Rumia wrote down a sequence:

$1 , 2 , 4 , 8 , 16 , 32 , 64 , 128 , \cdots , 2048 , 4096 , 8192 , 16384 , \cdots$.

Problem Description

Rumia: The general term of this sequence is $x_n = 2^{n-1}$.

Now, find how many numbers among the first $k+1$ terms have the first digit $4$ (for example, $4096$).

The input is “encrypted”. See [Input Format] for details.

Input Format

One line with two positive integers, $t$ and $k_0$.

If $t = 1$, then the actual $k$ is $k_0$.

If $t = 0$, then the actual $k$ is $10^{k_0}$.

Output Format

A single integer $ans$, representing how many numbers have the first digit $4$.

1 3

1

0 1

1

1 10

1

Hint

For $30\%$ of the testdata, $k_0 \leq 10^7, \ t = 1$.

For $70\%$ of the testdata, $k_0 \leq 10^9, \ t = 1$.

For another $30\%$ of the testdata, $k_0 \leq 233, \ t = 0$.

For $100\%$ of the testdata, $k_0 \geq 1$.

Translated by ChatGPT 5