Help me in solving RECUR05 problem

help
,
1

My issue

i need answer

My code

def fib(n):
    #Write your code here
    if(n==1):
        return "0";
    else:
        count =0;
        a,b=0,1;
        while count<n:
            nth = a+b;
            a=b;
            b=nth;
            count+=1;
        return a;
n = int(input())
print(fib(n))

Learning course: Design and Analysis of Algorithms
Problem Link: Fibonacci Series in Design and Analysis of Algorithms