TETRASUM - Sum of Tetranacci numbers (easy)

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The sequence of Tetranacci numbers is defined as follows:
an = an-1 + an-2 + an-3 + an-4 with a0 = a1 = a2 = 0 and a3 = 1.

Input

Input starts with a positive integer t ≤ 4000, then t lines follow. Each of the t lines contains two space separated integers m and n with 0 ≤ m ≤ n ≤ 109.

Output

Calculate am + am+1 + ... + an and print the result modulo 1000000007.

 

Example

Input:
2
1 2
1919 5393

Output:
0
66616

Note: If your solution is fast enough, you may try the classical version.


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numerix: 2012-03-13 14:03:41

Similar problems are SEQ and SPP.

Last edit: 2015-01-16 21:26:39

Added by:numerix
Date:2012-02-18
Time limit:5s
Source limit:10000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:own problem