Problem Statement
You are given a positive integer $L$ in base two. How many pairs of non-negative integers $(a, b)$ satisfy the following conditions?
$a + b \leq L$$a + b = a \text{ XOR } b$
Since there can be extremely many such pairs, print the count modulo $10^9 + 7$.
What is XOR? The XOR of integers $A$ and $B$, $A \text{ XOR } B$, is defined as follows: When $A \text{ XOR } B$ is written in base two, the digit in the $2^k$'s place ($k \geq 0$) is $1$ if either $A$ or $B$, but not both, has $1$ in the $2^k$'s place, and $0$ otherwise. For example, $3 \text{ XOR } 5 = 6$. (In base two: $011 \text{ XOR } 101 = 110$.)
Constraints
$L$is given in base two, without leading zeros.$1 \leq L < 2^{100\ 001}$
Input
Input is given from Standard Input in the following format:
L
Output
Print the number of pairs $(a, b)$ that satisfy the conditions, modulo $10^9 + 7$.
样例
10
5
1111111111111111111
162261460
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