Find any value in the Fibonacci sequence

Fibonacci sequence: 1 1 2 3 5 8 13...
Starting from the third number, each number is equal to the sum of the first two numbers.
Enter a number to indicate which Fibonacci number is

1. Recursion (when the number of inputs is too large, the efficiency is too slow)

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int Fib(int n)
{
    
    
	if (n <= 2)
		return 1;
	else
	    return Fib(n - 1) + Fib(n - 2);
}
int main()
{
    
    
	int n = 0;
	scanf("%d", &n);
	int ret = Fib(n);
	printf("%d\n", ret);
	return 0;
}

2. Non-recursive (iterative)

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int Fib(int m)
{
    
    
	int a = 1;
	int b = 1;
	int c = 1;
	while (m > 2)
	{
    
    
		c = a + b;
		a = b;
		b = c;
		m--;
	}
	return c;
}
int main()
{
    
    
	int n = 0;
	scanf("%d", &n);
	int ret = Fib(n);
	printf("%d\n", ret);
	return 0;
}