Use of C programming language coding

Input An integer n indicating the Fibonacci number needed. You can assume n ranges between 0 and 20 inclusively. Output An integer F_n. For example, if n=0, then F0=0. If n=1, then F1=1. If n=2, then F=1. etc Sample Input 2 Sample Input 3 Sample Input 5 Sample Output 5 14 377 Sample Input 6 Sample Output 6 20 6765