/* 
 * program to compute a Fibonacci number, using the following
 * definition:
 *
 * F(0) = 0
 * F(1) = 1
 * for n > 1, F(n) = F(n-2) + F(n-1)
 */
#include<stdio.h>

int fib(int n);

int main(void) {
    int n, r;
    printf("Enter an integer n:\n");
    scanf("%d", &n);
    r = fib(n);
    printf("\nF(n) = %d\n", r);
    return 0;
}

int fib(int n) {
    if (n <= 0) 
        return 0;
    else if (n == 1) 
        return 1;
    else
        return fib(n-1) + fib(n-2);
}