#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <cstring>
#include <queue>
#include <map>
#include <cmath>
#include <iomanip>
using namespace std;
#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair <int, int>
#define ull unsigned long long
// #define int long long
// #define int unsigned long long
const ll inf = 1e9 + 7;
const ll weirdMod = 998244353;
vector<pii> ans;
bool get(int n, int k) {
return ((n >> k) & 1);
}
void opr(int a, int b) {
ans.pb({a, b});
}
void solve() {
int n, s;
cin >> n >> s;
int arr[n + 1];
for (int i = 1; i <= n; i++)
cin >> arr[i];
if (s == 2) {
int lst = n;
for (int bt = 19; bt >= 0; bt--) {
int pos = -1;
for (int i = 1; i <= lst; i++)
if (get(arr[i], bt)) pos = i;
if (pos == -1) continue;
for (int i = pos + 1; i <= lst; i++) {
if (!get(arr[i], bt)) {
opr(i, i - 1); arr[i] ^= arr[i - 1];
}
} for (int i = pos - 1; i >= 1; i--) {
if (!get(arr[i], bt)) {
opr(i, i + 1); arr[i] ^= arr[i + 1];
}
}
for (int i = 2; i <= lst; i++) {
opr(i - 1, i); arr[i - 1] ^= arr[i];
} --lst;
}
} else {
int b[n + 1];
for (int i = 1; i <= n; i++)
b[i] = arr[i];
for (int i = 1; i < n; i++) {
opr(i, i + 1); arr[i] ^= arr[i + 1];
} int lst = n;
for (int i = 1; i <= n; i++) {
int pos = 1;
for (int j = 2; j <= lst; j++) {
if (b[pos] < b[j]) pos = j;
} for (int j = pos; j < lst; j++) {
opr(j + 1, j); arr[j + 1] ^= arr[j];
} for (int j = max(pos - 1, 1); j < lst; j++) {
opr(j, j + 1); arr[j] ^= arr[j + 1];
} for (int j = pos; j < lst; j++)
swap(b[j], b[j + 1]);
--lst;
}
}
cout << ans.size() << '\n';
for (auto [a, b] : ans) cout << a << ' ' << b << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
int t = 1;
// cin >> t;
while (t--) {
solve();
cout << '\n';
}
return 0;
}
