#include <stdio.h>
#include <stdlib.h>
int fib(int n);
int main (int argc, char **argv) {
int n;
if (argc < 2)
return 1;
n = atoi(argv[1]);
if (n < 1)
return 1;
printf("%d\n", fib(n));
return 0;
}
int fib(int n) {
if (n == 1 | n == 2)
return 1;
return fib(n-1) + fib(n-2);
}