Problem:
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Fibonacci Number

Write a program which prints $n$-th fibonacci number for a given integer $n$. The $n$-th fibonacci number is defined by the following recursive formula:

\begin{equation*}
fib(n)= \left \{
\begin{array}{ll}
1　 & (n = 0) \\
1　 & (n = 1) \\
fib(n - 1) + fib(n - 2) & \\
\end{array}
\right.
\end{equation*}

Input

An integer $n$ is given.

output

Print the $n$-th fibonacci number in a line.

Constraints

$0 \leq n \leq 44$

Sample Input 1

3

Sample Output 1

3

Solution in C (judge verdict: Time Limit Exceeded)

#include<stdio.h>

int fib(int);

main(){

  int n,a;
  scanf("%d",&n);
  a=fib(n);

  printf("%d\n",a);
  return 0;
}

int fib(int c)
{
  int f;
  if(c == 0 || c == 1 ){
    return 1; 
  }

  if(c > 0 && c >=2 ){
    f = fib(c-1)+fib(c-2);
    return f;
  }
}