Fibonacci Sequence Calculation

Given an integer N (where N \ge 2), compute the N-th Fibonacci number.

The Fibonacci sequence is defined as follows:

\(F_0 = 0\), \(F_1 = 1\), and for \(n \ge 2\), \(F_n = F_{n-1} + F_{n-2}\).

For example, if N is 2 the result is 1 since \(F_2 = 1\); if N is 10 the result is 55 because \(F_{10} = 55\); and if N is 50 the answer is 12586269025.

inputFormat

The input consists of a single integer N from standard input.

outputFormat

Output the N-th Fibonacci number to standard output.

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