n = int(input())
lst = [0] * n
if n % 2 != 0:
print("-1")
else:
for i in range(0, n):
if i % 2 == 0:
lst[i+1] = i + 1
else:
lst[i-1] = i + 1
finLst = [str(x) for x in lst]
print(" ".join(finLst))
#include <bits/stdc++.h>
using namespace std;
int main()
{
int n;
cin >> n;
int a[n];
for (int i = 1; i <= n; i++)
{
a[i] = i;
}
if (n % 2 != 0)
cout << "-1" << endl;
else
{
for (int i = 1; i <= n-1; i += 2)
{
swap(a[i], a[i+1]);
}
for (int i = 1; i <= n; i++)
{
cout << a[i] << " ";
}
}
return 0;
}1614B - Divan and a New Project | 791A - Bear and Big Brother |
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