use std::io::{self, *}; struct Solution{ } impl Solution{ pub fn fib(n: i32) -> i32 { if n <= 2 { return 1; } return Solution::fib(n-1) + Solution::fib(n-2); } } fn main() { let mut n : i32 = 0; let mut input = String::new(); io::stdin().read_line(&mut input); n = input.trim().parse().expect(""); print!("{}", Solution::fib(n)); }