#include <bits/stdc++.h>
#define pb push_back
#define int long long
using namespace std;
const int N=1e3+5,LOG=20;
int v[N];
signed main()
{
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
int n,cer;
cin>>n>>cer;
for(int i=1;i<=n;++i) cin>>v[i];
vector<pair<int,int>> sol;
for(int b=0;b<LOG;++b)
{
for(int i=1;i+1<=n;++i)
{
if(!(v[i]&(1<<b))) continue;
if(v[i+1]&(1<<b))
{
sol.pb({i,i+1});
v[i]^=v[i+1];
}
else
{
sol.pb({i+1,i});
v[i+1]^=v[i];
sol.pb({i,i+1});
v[i]^=v[i+1];
}
}
}
//for(int i=1;i<=n;++i) cout<<v[i]<<" ";
//cout<<'\n';
cout<<sol.size()<<'\n';
for(auto x:sol) cout<<x.first<<" "<<x.second<<'\n';
}
