The Fibonacci sequence starts 0, 1, 1, 2, 3, 5, 8, … where each number is the sum of the two before it (F(0) = 0, F(1) = 1).
Read n and print F(n).
Input
One integer 0 ≤ n ≤ 60.
Output
F(n). Use a loop – naive recursion is far too slow for n = 60 – and a 64-bit integer type.
Read from standard input and write to standard output. 5 test cases in total (3 hidden). Tests for this language run inside your browser.