#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 */
int /*<<< orphan*/ printf(char *, char *);
int /*<<< orphan*/ revstr(char *, int);
int /*<<< orphan*/ scanf(char *, ...);
int main() {
  int n, i;
  scanf("%d\n", &n);
  char str[n];
  for (i = 0; i < n; i++) {
    scanf("%c", &str[i]);
  }
  revstr(str, n - 1);
  printf("%s", str);
  return (0);
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeba(%rip),%rdi
xor    %eax,%eax
lea    -0x8(%rbp),%rsi
call   1050 <scanf@plt>
mov    -0x8(%rbp),%eax
mov    %rsp,%rcx
mov    %rcx,-0x18(%rbp)
mov    %rax,%rdx
add    $0xf,%rdx
and    $0xfffffffffffffff0,%rdx
mov    %rsp,%rcx
sub    %rdx,%rcx
mov    %rcx,-0x28(%rbp)
mov    %rcx,%rsp
mov    %rax,-0x20(%rbp)
movl   $0x0,-0xc(%rbp)
mov    -0xc(%rbp),%eax
cmp    -0x8(%rbp),%eax
jge    11b1 <main+0x81>
mov    -0x28(%rbp),%rsi
movslq -0xc(%rbp),%rax
add    %rax,%rsi
lea    0xe68(%rip),%rdi
mov    $0x0,%al
call   1050 <scanf@plt>
mov    -0xc(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0xc(%rbp)
jmp    117e <main+0x4e>
mov    -0x28(%rbp),%rdi
mov    -0x8(%rbp),%esi
sub    $0x1,%esi
call   1030 <revstr@plt>
mov    -0x28(%rbp),%rsi
lea    0xe3c(%rip),%rdi
call   1040 <printf@plt>
movl   $0x0,-0x4(%rbp)
mov    -0x18(%rbp),%rax
mov    %rax,%rsp
mov    -0x4(%rbp),%eax
mov    %rbp,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbp
mov    %rsp,%rbp
push   %r15
push   %r14
push   %r12
push   %rbx
sub    $0x10,%rsp
lea    0xeba(%rip),%rdi
lea    -0x24(%rbp),%rsi
xor    %eax,%eax
call   1050 <scanf@plt>
mov    %rsp,%r15
mov    -0x24(%rbp),%eax
mov    %rsp,%r12
add    $0xf,%rax
and    $0xfffffffffffffff0,%rax
sub    %rax,%r12
mov    %r12,%rsp
mov    -0x24(%rbp),%esi
test   %esi,%esi
jle    119b <main+0x6b>
lea    0xe8e(%rip),%r14
xor    %ebx,%ebx
nopl   0x0(%rax,%rax,1)
lea    (%r12,%rbx,1),%rsi
mov    %r14,%rdi
xor    %eax,%eax
call   1050 <scanf@plt>
add    $0x1,%rbx
movslq -0x24(%rbp),%rsi
cmp    %rsi,%rbx
jl     1180 <main+0x50>
add    $0xffffffff,%esi
mov    %r12,%rdi
call   1030 <revstr@plt>
lea    0xe5a(%rip),%rdi
mov    %r12,%rsi
call   1040 <printf@plt>
mov    %r15,%rsp
xor    %eax,%eax
lea    -0x20(%rbp),%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
@.str = [4 x i8] c"%d\0A\00"
@.str.1 = [3 x i8] c"%c\00"
@.str.2 = [3 x i8] c"%s\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca i32
%4 = alloca i8*
%5 = alloca i64
store i32 0, i32* %1
%6 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32* %2)
%7 = load i32, i32* %2
%8 = zext i32 %7 to i64
%9 = call i8* @llvm.stacksave()
store i8* %9, i8** %4
%10 = alloca i8, i64 %8
store i64 %8, i64* %5
store i32 0, i32* %3
br label %11
11: ; preds = %20, %0
%12 = load i32, i32* %3
%13 = load i32, i32* %2
%14 = icmp slt i32 %12, %13
br i1 %14, label %15, label %23
15: ; preds = %11
%16 = load i32, i32* %3
%17 = sext i32 %16 to i64
%18 = getelementptr inbounds i8, i8* %10, i64 %17
%19 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %18)
br label %20
20: ; preds = %15
%21 = load i32, i32* %3
%22 = add nsw i32 %21, 1
store i32 %22, i32* %3
br label %11
23: ; preds = %11
%24 = load i32, i32* %2
%25 = sub nsw i32 %24, 1
%26 = call i32 @revstr(i8* %10, i32 %25)
%27 = call i32 @printf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i8* %10)
store i32 0, i32* %1
%28 = load i8*, i8** %4
%29 = load i32, i32* %1
ret i32 %29
}

LLVM IR (-O2):
@.str = [4 x i8] c"%d\0A\00"
@.str.1 = [3 x i8] c"%c\00"
@.str.2 = [3 x i8] c"%s\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32* %1)
%4 = load i32, i32* %1
%5 = zext i32 %4 to i64
%6 = call i8* @llvm.stacksave()
%7 = alloca i8, i64 %5
%8 = load i32, i32* %1
%9 = icmp sgt i32 %8, 0
br i1 %9, label %10, label %18
10: ; preds = %0, %10
%11 = phi i64 [ %14, %10 ], [ 0, %0 ]
%12 = getelementptr inbounds i8, i8* %7, i64 %11
%13 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %12)
%14 = add nuw nsw i64 %11, 1
%15 = load i32, i32* %1
%16 = sext i32 %15 to i64
%17 = icmp slt i64 %14, %16
br i1 %17, label %10, label %18
18: ; preds = %10, %0
%19 = phi i32 [ %8, %0 ], [ %15, %10 ]
%20 = add nsw i32 %19, -1
%21 = call i32 @revstr(i8* %7, i32 %20)
%22 = call i32 @printf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i8* %7)
ret i32 0
}