T157289 Coda's Fibonacci Password

Raki, AC_Crush and Rex are members of ACM TEAM. If they want to submit problems to [acmoj.gxb.sspu.edu.cn](acmoj.gxb.sspu.edu.cn), they should submit it to Coda at first. if they try to persecution Coda in problem background, Coda will refuse it. One day, Raki passed by Coda's laptop, he noticed that Coda's admin account password is a number in the Fibonacci sequence. If they have password, they can update problem as they want. Now, Raki knows the $i$, Coda's password is $f[i]$, please transfer the $i$ to Coda's password!

Fibonacci sequence is defined as following rules: 1. $f[1]=f[2]=1$ 2. $f[n]=f[n-1]+f[n-2] (n>=3)$

One line, an integer $i$.

One line, an interger, please output $f[i]$.

$1