#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 *, int);
int /*<<< orphan*/ scanf(char *, int *);
int main() {
  int i, j, c, len, num, temp, t, res;
  int xo = 0;
  scanf("%d", &num);
  for (i = 0; i < num; i++) {
    scanf("%d", &temp);
    xo = xo ^ temp;
  }
  printf("%d\n", xo);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
movl   $0x0,-0x4(%rbp)
movl   $0x0,-0x28(%rbp)
lea    0xec3(%rip),%rdi
lea    -0x18(%rbp),%rsi
call   1040 <scanf@plt>
movl   $0x0,-0x8(%rbp)
mov    -0x8(%rbp),%eax
cmp    -0x18(%rbp),%eax
jge    1180 <main+0x60>
lea    0xea0(%rip),%rdi
lea    -0x1c(%rbp),%rsi
call   1040 <scanf@plt>
mov    -0x28(%rbp),%eax
xor    -0x1c(%rbp),%eax
mov    %eax,-0x28(%rbp)
mov    -0x8(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x8(%rbp)
jmp    114d <main+0x2d>
mov    -0x28(%rbp),%esi
lea    0xe79(%rip),%rdi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
lea    0xed2(%rip),%rdi
mov    %rsp,%rsi
call   1040 <scanf@plt>
cmpl   $0x0,(%rsp)
jle    1169 <main+0x49>
xor    %ebx,%ebx
lea    0xebb(%rip),%r14
lea    0x4(%rsp),%r15
xor    %ebp,%ebp
nopl   0x0(%rax)
mov    %r14,%rdi
mov    %r15,%rsi
call   1040 <scanf@plt>
xor    0x4(%rsp),%ebx
add    $0x1,%ebp
cmp    (%rsp),%ebp
jl     1150 <main+0x30>
jmp    116b <main+0x4b>
xor    %ebx,%ebx
lea    0xe91(%rip),%rdi
mov    %ebx,%esi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

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

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