#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
using ll = long long;
ll n,k,i,a[1007];
vector<pair<ll,ll>> res;
int main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n>>k;
if (k==1) {
for (i=1;i<=n;i++) cin>>a[i];
for (i=1;i<=n;i++) {
if (a[i]<=a[i-1]) {
if (min(a[i]^a[i-1],a[i]^a[i+1])>a[i-1]) {
a[i] = min(a[i]^a[i-1],a[i]^a[i+1]);
if (min(a[i]^a[i-1],a[i]^a[i+1])==a[i]^a[i-1]) res.push_back({i,i-1});
else res.push_back({i,i+1});
}
else {
a[i] = max(a[i]^a[i-1],a[i]^a[i+1]);
if (max(a[i]^a[i-1],a[i]^a[i+1])==a[i]^a[i-1]) res.push_back({i,i-1});
else res.push_back({i,i+1});
}
}
}
cout<<res.size()<<endl;
for (auto x:res) cout<<x.first<<' '<<x.second<<endl;
}
return 0;
}
