CF758F.Geometrical Progression
普及/提高-
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题目描述
For given n , l and r find the number of distinct geometrical progression, each of which contains n distinct integers not less than l and not greater than r . In other words, for each progression the following must hold: l<=ai<=r and ai=aj , where a1,a2,...,an is the geometrical progression, 1<=i,j<=n and i=j .
Geometrical progression is a sequence of numbers a1,a2,...,an where each term after first is found by multiplying the previous one by a fixed non-zero number d called the common ratio. Note that in our task d may be non-integer. For example in progression 4,6,9 , common ratio is .
Two progressions a1,a2,...,an and b1,b2,...,bn are considered different, if there is such i ( 1<=i<=n ) that ai=bi .
输入格式
The first and the only line cotains three integers n , l and r ( 1<=n<=107,1<=l<=r<=107 ).
输出格式
Print the integer K — is the answer to the problem.
输入输出样例
输入#1
1 1 10
输出#1
10
输入#2
2 6 9
输出#2
12
输入#3
3 1 10
输出#3
8
输入#4
3 3 10
输出#4
2
说明/提示
These are possible progressions for the first test of examples:
- 1 ;
- 2 ;
- 3 ;
- 4 ;
- 5 ;
- 6 ;
- 7 ;
- 8 ;
- 9 ;
- 10 .
These are possible progressions for the second test of examples:
- 6,7 ;
- 6,8 ;
- 6,9 ;
- 7,6 ;
- 7,8 ;
- 7,9 ;
- 8,6 ;
- 8,7 ;
- 8,9 ;
- 9,6 ;
- 9,7 ;
- 9,8 .
These are possible progressions for the third test of examples:
- 1,2,4 ;
- 1,3,9 ;
- 2,4,8 ;
- 4,2,1 ;
- 4,6,9 ;
- 8,4,2 ;
- 9,3,1 ;
- 9,6,4 .
These are possible progressions for the fourth test of examples:
- 4,6,9 ;
- 9,6,4 .