#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */

/* Variables and functions */
double pow(int, int);
int /*<<< orphan*/ printf(char *, double);
int /*<<< orphan*/ scanf(char *, int *);
double sqrt(double);
int main(void) {
  int n;
  double sqrt5 = sqrt(5.0);
  scanf("%d", &n);
  printf("%.1lf\n",
         (pow((1 + sqrt5) / 2.0, n) - pow((1 - sqrt5) / 2.0, n)) / sqrt5);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
movsd  0xeb9(%rip),%xmm0
call   1060 <sqrt@plt>
movsd  %xmm0,-0x10(%rbp)
lea    0xeb0(%rip),%rdi
lea    -0x8(%rbp),%rsi
call   1040 <scanf@plt>
movsd  0xe8f(%rip),%xmm0
addsd  -0x10(%rbp),%xmm0
movsd  0xe7a(%rip),%xmm1
divsd  %xmm1,%xmm0
cvttsd2si %xmm0,%edi
mov    -0x8(%rbp),%esi
call   1050 <pow@plt>
movsd  %xmm0,-0x18(%rbp)
movsd  0xe65(%rip),%xmm0
subsd  -0x10(%rbp),%xmm0
movsd  0xe50(%rip),%xmm1
divsd  %xmm1,%xmm0
cvttsd2si %xmm0,%edi
mov    -0x8(%rbp),%esi
call   1050 <pow@plt>
movaps %xmm0,%xmm1
movsd  -0x18(%rbp),%xmm0
subsd  %xmm1,%xmm0
divsd  -0x10(%rbp),%xmm0
lea    0xe43(%rip),%rdi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
sub    $0x18,%rsp
lea    0xecd(%rip),%rdi
lea    0xc(%rsp),%rsi
call   1040 <scanf@plt>
mov    0xc(%rsp),%esi
mov    $0x1,%edi
call   1050 <pow@plt>
movsd  %xmm0,0x10(%rsp)
mov    0xc(%rsp),%esi
xor    %edi,%edi
call   1050 <pow@plt>
movsd  0x10(%rsp),%xmm1
subsd  %xmm0,%xmm1
divsd  0xe8a(%rip),%xmm1
movapd %xmm1,%xmm0
lea    0xe8a(%rip),%rdi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x18,%rsp
ret

LLVM IR (-O0):
@.str = [3 x i8] c"%d\00"
@.str.1 = [7 x i8] c"%.1lf\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca double
store i32 0, i32* %1
%4 = call double @sqrt(double 5.000000e+00)
store double %4, double* %3
%5 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i32* %2)
%6 = load double, double* %3
%7 = fadd double 1.000000e+00, %6
%8 = fdiv double %7, 2.000000e+00
%9 = fptosi double %8 to i32
%10 = load i32, i32* %2
%11 = call double @pow(i32 %9, i32 %10)
%12 = load double, double* %3
%13 = fsub double 1.000000e+00, %12
%14 = fdiv double %13, 2.000000e+00
%15 = fptosi double %14 to i32
%16 = load i32, i32* %2
%17 = call double @pow(i32 %15, i32 %16)
%18 = fsub double %11, %17
%19 = load double, double* %3
%20 = fdiv double %18, %19
%21 = call i32 @printf(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i64 0, i64 0), double %20)
ret i32 0
}

LLVM IR (-O2):
@.str = [3 x i8] c"%d\00"
@.str.1 = [7 x i8] c"%.1lf\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i32* %1)
%4 = load i32, i32* %1
%5 = call double @pow(i32 1, i32 %4)
%6 = load i32, i32* %1
%7 = call double @pow(i32 0, i32 %6)
%8 = fsub double %5, %7
%9 = fdiv double %8, 0x4001E3779B97F4A8
%10 = call i32 @printf(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i64 0, i64 0), double %9)
ret i32 0
}