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Problems > Tribonacci Modulo

Tribonacci Modulo

Difficulty: 1750 4000 ms 128 MB

matrix-exponentiation

The Tribonacci sequence is T(0)=0, T(1)=T(2)=1, T(n)=T(n−1)+T(n−2)+T(n−3). Print T(N) modulo 109+7.

Input: one integer N.

Output: the value modulo 109+7.

Constraints:

  • 1 ≤ N ≤ 1018

Sample Tests

Input 1
4
Output 1
4
Input 2
0
Output 2
0
Input 3
1000000000000000000
Output 3
926781415

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