#include <bits/stdc++.h>
#define int long long
#define ll long long
#define ld long double
using namespace std;
const int mxn = 1005;
const int SQRT = 500;
const int LOG = 20;
const int inf = 1e18;
const int mod = 998244353;
const ld eps = 1e-9;
int n;
int A[mxn];
vector<pair<int,int> >res;
void op(int a,int b){
res.push_back({a+1,b+1});
A[a] ^= A[b];
}
inline bool bit(int x,int i){
return x & (1 << i);
}
void s1(){
int B[n];
for(int i = 0;i<n;i++)B[i] = A[i];
for(int i = 0;i<n-1;i++)op(i,i + 1);
for(int i = n-1;i>=0;i--){
int k = 0;
for(int j = 1;j<=i;j++){
if(B[j] > B[k])k = j;
}
for(int j = k+1;j<=i;j++)op(j,j-1);
for(int j = k-1;j<i;j++){
if(j != -1)op(j,j+1);
}
for(int j = k;j<i;j++)swap(B[j], B[j+1]);
}
}
void s2(){
int last = n;
for (int i = LOG-1; i >= 0; i--){
bool ok = false;
for (int j = 0; j < n; j++)
if (bit(A[j], i)){
ok = true;
break;
}
if (!ok) continue;
last--;
for (int j = 0; j < last; j++)
if (bit(A[j], i) && !bit(A[j+1], i)){
op(j+1, j);
op(j, j+1);
}
else if (bit(A[j], i) && bit(A[j+1], i)){
op(j, j+1);
}
}
}
void solve(int T){
cin>>n;
int s;
cin>>s;
for(int i = 0;i<n;i++)cin>>A[i];
if(s == 1)s1();
else s2();
cout<<res.size()<<endl;
for(auto p : res)cout<<p.first<<" "<<p.second<<endl;
}
int32_t main(){
#ifdef ONLINE_JUDGE
ios::sync_with_stdio(false);
cin.tie(0);
#endif
int t = 1;
//cin>>t;
for(int i = 1;i<=t;i++)solve(i);
return 0;
}
