#include <iostream>
#include <vector>
using namespace std;
const int maxn = 1005;
int n, s;
int a[maxn];
void fastIO()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int main()
{
fastIO();
cin >> n >> s;
for (int i = 1; i <= n; ++i)
{
cin >> a[i];
}
vector<pair<int, int>> ans;
if (s == 1)
{
int last = 0;
for (int i = n; i > 1; --i)
{
int idx = 1;
for (int j = 1; j <= i; ++j)
{
if ((a[j] ^ last) > (a[idx] ^ last))
{
idx = j;
}
}
for (int j = 1; j <= i; ++j)
{
if (j != n)
{
ans.push_back(make_pair(j, j + 1));
a[j] = (a[j] ^ a[j + 1]);
}
}
for (int j = idx + 1; j <= i; ++j)
{
ans.push_back(make_pair(j, j - 1));
a[j] = (a[j] ^ a[j - 1]);
}
for (int j = idx - 1; j > 1; --j)
{
ans.push_back(make_pair(j - 1, j));
a[j - 1] = (a[j - 1] ^ a[j]);
}
/*for (int j = 1; j <= n; ++j)
{
cout << a[j] << ' ';
}
cout << endl;*/
last = a[i];
}
ans.push_back(make_pair(1, 2));
a[1] = (a[1] ^ a[2]);
}
else
{
for (int bit = 19; bit >= 0; --bit)
{
for (int i = 1; i < n; ++i)
{
if (((a[i] & (1 << bit)) != 0) && ((a[i + 1] & (1 << bit)) == 0))
{
a[i + 1] = (a[i] ^ a[i + 1]);
ans.push_back(make_pair(i + 1, i));
}
if (((a[i] & (1 << bit)) != 0) && ((a[i + 1] ^ a[i]) < a[i]))
{
a[i] = (a[i] ^ a[i + 1]);
ans.push_back(make_pair(i, i + 1));
}
}
}
}
/*for (int i = 1; i <= n; ++i)
{
cout << a[i] << ' ';
}
cout << endl;*/
cout << ans.size() << endl;
for (auto [x, y] : ans)
{
cout << x << ' ' << y << "\n";
}
return 0;
}
