#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 n, a[101], i, s;
  scanf("%d", &n);
  for (i = 0; i < 101; ++i)
    a[i] = 0;
  for (i = 0; i < n; ++i) {
    scanf("%d", &s);
    a[s]++;
  }
  for (i = 0; i < 101; ++i)
    if (a[i] & 0x1) {
      printf("%d\n", i);
      break;
    }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x1b0,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xec7(%rip),%rdi
lea    -0x8(%rbp),%rsi
call   1040 <scanf@plt>
movl   $0x0,-0x1a4(%rbp)
cmpl   $0x65,-0x1a4(%rbp)
jge    117f <main+0x5f>
movslq -0x1a4(%rbp),%rax
movl   $0x0,-0x1a0(%rbp,%rax,4)
mov    -0x1a4(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x1a4(%rbp)
jmp    114c <main+0x2c>
movl   $0x0,-0x1a4(%rbp)
mov    -0x1a4(%rbp),%eax
cmp    -0x8(%rbp),%eax
jge    11d7 <main+0xb7>
lea    0xe61(%rip),%rdi
lea    -0x1a8(%rbp),%rsi
call   1040 <scanf@plt>
movslq -0x1a8(%rbp),%rax
mov    -0x1a0(%rbp,%rax,4),%ecx
add    $0x1,%ecx
mov    %ecx,-0x1a0(%rbp,%rax,4)
mov    -0x1a4(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x1a4(%rbp)
jmp    1189 <main+0x69>
movl   $0x0,-0x1a4(%rbp)
cmpl   $0x65,-0x1a4(%rbp)
jge    1238 <main+0x118>
movslq -0x1a4(%rbp),%rax
mov    -0x1a0(%rbp,%rax,4),%eax
and    $0x1,%eax
cmp    $0x0,%eax
je     121f <main+0xff>
mov    -0x1a4(%rbp),%esi
lea    0xdee(%rip),%rdi
call   1030 <printf@plt>
jmp    1238 <main+0x118>
jmp    1224 <main+0x104>
mov    -0x1a4(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x1a4(%rbp)
jmp    11e1 <main+0xc1>
xor    %eax,%eax
add    $0x1b0,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbp
push   %r14
push   %rbx
sub    $0x1b0,%rsp
lea    0xebe(%rip),%rdi
lea    0x8(%rsp),%rsi
call   1050 <scanf@plt>
lea    0x10(%rsp),%rdi
xor    %ebp,%ebp
mov    $0x194,%edx
xor    %esi,%esi
call   1040 <memset@plt>
cmpl   $0x0,0x8(%rsp)
jle    119e <main+0x6e>
lea    0xe93(%rip),%r14
lea    0xc(%rsp),%rbx
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax)
mov    %r14,%rdi
mov    %rbx,%rsi
call   1050 <scanf@plt>
movslq 0xc(%rsp),%rax
addl   $0x1,0x10(%rsp,%rax,4)
add    $0x1,%ebp
cmp    0x8(%rsp),%ebp
jl     1180 <main+0x50>
mov    $0x3,%esi
testb  $0x1,0x4(%rsp,%rsi,4)
jne    11d6 <main+0xa6>
nopw   0x0(%rax,%rax,1)
cmp    $0x67,%rsi
je     11f2 <main+0xc2>
testb  $0x1,0x8(%rsp,%rsi,4)
jne    11dc <main+0xac>
testb  $0x1,0xc(%rsp,%rsi,4)
jne    11e2 <main+0xb2>
testb  $0x1,0x10(%rsp,%rsi,4)
jne    11e6 <main+0xb6>
add    $0x4,%rsi
testb  $0x1,0x4(%rsp,%rsi,4)
je     11b0 <main+0x80>
add    $0xfffffffffffffffd,%rsi
jmp    11e6 <main+0xb6>
add    $0xfffffffffffffffe,%rsi
jmp    11e6 <main+0xb6>
add    $0xffffffffffffffff,%rsi
lea    0xe16(%rip),%rdi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x1b0,%rsp
pop    %rbx
pop    %r14
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 [101 x i32]
%4 = alloca i32
%5 = alloca i32
store i32 0, i32* %1
%6 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i32* %2)
store i32 0, i32* %4
br label %7
7: ; preds = %14, %0
%8 = load i32, i32* %4
%9 = icmp slt i32 %8, 101
br i1 %9, label %10, label %17
10: ; preds = %7
%11 = load i32, i32* %4
%12 = sext i32 %11 to i64
%13 = getelementptr inbounds [101 x i32], [101 x i32]* %3, i64 0, i64 %12
store i32 0, i32* %13
br label %14
14: ; preds = %10
%15 = load i32, i32* %4
%16 = add nsw i32 %15, 1
store i32 %16, i32* %4
br label %7
17: ; preds = %7
store i32 0, i32* %4
br label %18
18: ; preds = %29, %17
%19 = load i32, i32* %4
%20 = load i32, i32* %2
%21 = icmp slt i32 %19, %20
br i1 %21, label %22, label %32
22: ; preds = %18
%23 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i32* %5)
%24 = load i32, i32* %5
%25 = sext i32 %24 to i64
%26 = getelementptr inbounds [101 x i32], [101 x i32]* %3, i64 0, i64 %25
%27 = load i32, i32* %26
%28 = add nsw i32 %27, 1
store i32 %28, i32* %26
br label %29
29: ; preds = %22
%30 = load i32, i32* %4
%31 = add nsw i32 %30, 1
store i32 %31, i32* %4
br label %18
32: ; preds = %18
store i32 0, i32* %4
br label %33
33: ; preds = %47, %32
%34 = load i32, i32* %4
%35 = icmp slt i32 %34, 101
br i1 %35, label %36, label %50
36: ; preds = %33
%37 = load i32, i32* %4
%38 = sext i32 %37 to i64
%39 = getelementptr inbounds [101 x i32], [101 x i32]* %3, i64 0, i64 %38
%40 = load i32, i32* %39
%41 = and i32 %40, 1
%42 = icmp ne i32 %41, 0
br i1 %42, label %43, label %46
43: ; preds = %36
%44 = load i32, i32* %4
%45 = call i32 @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i32 %44)
br label %50
46: ; preds = %36
br label %47
47: ; preds = %46
%48 = load i32, i32* %4
%49 = add nsw i32 %48, 1
store i32 %49, i32* %4
br label %33
50: ; preds = %43, %33
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 [101 x i32]
%3 = bitcast [101 x i32]* %2 to i8*
%4 = alloca i32
%5 = bitcast i32* %1 to i8*
%6 = bitcast i32* %4 to i8*
%7 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i32* %1)
%8 = load i32, i32* %1
%9 = icmp sgt i32 %8, 0
br i1 %9, label %10, label %21
10: ; preds = %0, %10
%11 = phi i32 [ %18, %10 ], [ 0, %0 ]
%12 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i32* %4)
%13 = load i32, i32* %4
%14 = sext i32 %13 to i64
%15 = getelementptr inbounds [101 x i32], [101 x i32]* %2, i64 0, i64 %14
%16 = load i32, i32* %15
%17 = add nsw i32 %16, 1
store i32 %17, i32* %15
%18 = add nuw nsw i32 %11, 1
%19 = load i32, i32* %1
%20 = icmp slt i32 %18, %19
br i1 %20, label %10, label %21
21: ; preds = %10, %0
br label %22
22: ; preds = %52, %21
%23 = phi i64 [ 0, %21 ], [ %53, %52 ]
%24 = getelementptr inbounds [101 x i32], [101 x i32]* %2, i64 0, i64 %23
%25 = load i32, i32* %24
%26 = and i32 %25, 1
%27 = icmp eq i32 %26, 0
br i1 %27, label %32, label %28
28: ; preds = %46, %40, %35, %22
%29 = phi i64 [ %23, %22 ], [ %33, %35 ], [ %41, %40 ], [ %47, %46 ]
%30 = trunc i64 %29 to i32
%31 = call i32 @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i32 %30)
br label %54
32: ; preds = %22
%33 = or i64 %23, 1
%34 = icmp eq i64 %33, 101
br i1 %34, label %54, label %35
35: ; preds = %32
%36 = getelementptr inbounds [101 x i32], [101 x i32]* %2, i64 0, i64 %33
%37 = load i32, i32* %36
%38 = and i32 %37, 1
%39 = icmp eq i32 %38, 0
br i1 %39, label %40, label %28
40: ; preds = %35
%41 = or i64 %23, 2
%42 = getelementptr inbounds [101 x i32], [101 x i32]* %2, i64 0, i64 %41
%43 = load i32, i32* %42
%44 = and i32 %43, 1
%45 = icmp eq i32 %44, 0
br i1 %45, label %46, label %28
46: ; preds = %40
%47 = or i64 %23, 3
%48 = getelementptr inbounds [101 x i32], [101 x i32]* %2, i64 0, i64 %47
%49 = load i32, i32* %48
%50 = and i32 %49, 1
%51 = icmp eq i32 %50, 0
br i1 %51, label %52, label %28
52: ; preds = %46
%53 = add nuw nsw i64 %23, 4
br label %22
54: ; preds = %32, %28
ret i32 0
}