As a tradition, every year before IOI all the members of Natalia Fan Club are invited to Malek Dance Club to have a fun night together. Malek Dance Club has 2 n members and coincidentally Natalia Fan Club also has 2 n members. Each member of MDC is assigned a unique id i from 0 to 2 n - 1. The same holds for each member of NFC. One of the parts of this tradition is one by one dance, where each member of MDC dances with a member of NFC. A dance pair is a pair of numbers (a, b) such that member a from MDC dances with member b from NFC. The complexity of a pairs' assignment is the number of pairs of dancing pairs (a, b) and (c, d) such that a c and b d . You are given a binary number of length n named x . We know that member i from MDC dances with member from NFC. Your task is to calculate the complexity of this assignment modulo 1000000007 (109 + 7). Expression denotes applying «XOR» to numbers x and y . This operation exists in all modern programming languages, for example, in C++ and Java it denotes as «^», in Pascal — «xor».
输入描述:
The first line of input contains a binary number x of lenght n, (1 ≤ n ≤ 100).This number may contain leading zeros.
输出描述:
Print the complexity of the given dance assignent modulo 1000000007(109 + 7).
加载中...