#include<bits/stdc++.h>
using namespace std;
int main () {
int n, s;
cin >> n >> s;
int a[n];
for(int i = 0;i<n;i++)cin >> a[i];
vector<pair<int,int>> op;
if(s==2) {
for(int i = 19;i>=0;i--) {
for(int j = 1;j<n;j++) {
if((a[j]&(1<<i))==0 and (a[j-1]&(1<<i))!=0) {
a[j]^=a[j-1];
op.push_back({j,j-1});
}
if((a[j-1]&(1<<i))!=0) {
if((a[j-1]^a[j])<a[j-1]) {
a[j-1]^=a[j];
op.push_back({j-1,j});
}
}
}
}
cout << op.size() << "\n";
for(auto i:op) {
cout << i.first+1 << " " << i.second+1 << "\n";
}
}
else {
int x=0;
for(int i = 0;i<n-1;i++) {
int mx=0;
for(int j = 0;j<n-i;j++) {
if((a[j]^x)>(a[mx]^x))mx=j;
}
for(int j = 0;j<n-i;j++) {
if(j!=n-1) {
op.push_back({j,j+1});
a[j]^=a[j+1];
}
}
for(int j = mx;j<n-i-1;j++) {
a[j+1]^=a[j];
op.push_back({j+1,j});
}
for(int j = mx-2;j>=0;j--) {
a[j]^=a[j+1];
op.push_back({j,j+1});
}
x=a[n-i-1];
}
a[0]^=a[1];
op.push_back({0,1});
cout << op.size() << "\n";
for(auto i:op) {
cout << i.first+1 << " " << i.second+1 << "\n";
}
}
}
