C :

#include <stdio.h>

int f(int a)
{
	if (a == 1)
		return 1;
	if (a == 0)
		return 0;
	return f(a - 1) + f(a - 2);
}

int main()
{
	int n;
	while (scanf("%d", &n) != EOF)
	{
		printf("%d\n", f(n-1));
	}
}

C++ :

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iomanip>
#include <iostream>
using namespace std;
int dg(int);
int main()
{
	int n;
	cin>>n;
	cout<<dg(n);
	return 0;
}
int dg(int i)
{
	if (i == 1)
		return 0;
	else if (i == 2)
		return 1;
	else
		return dg(i - 1) + dg(i - 2);
}

Pascal :

function fbnq(a:longint):longint;
begin
if a=1 then fbnq:=0
        else if a=2 then fbnq:=1
                else fbnq:=fbnq(a-1)+fbnq(a-2);
end;
var
a:longint;
begin
readln(a);
writeln(fbnq(a));
end.