#include<iostream>
#include<vector>
#include<map>
using namespace std;
int P, N;
void p1() {
int cnt1 = 1, cnt2 = 1;
cout<<N/2<<endl;
for(int idx = 0; idx<N-1; idx++) {
if(idx<N/2) {
cout<<cnt1++<<endl;
}else {
cout<<cnt2++<<endl;
}
}
}
void p2() {
int g1 = -1, g2 = -1;
map<int,int> mp1, mp2;
vector<int> nums(N);
for(int i=0; i<N; i++) {
int in;
cin>>in;
nums[i] = in;
mp1[i] = -1;
mp2[i] = -1;
}
for(int i=0; i<N; i++) {
if(i<N/2) {
if(mp1[nums[i]]!=-1) {
g1 = mp1[nums[i]];
g2 = i;
break;
}
mp1[nums[i]] = i;
}else {
if(mp2[nums[i]] != -1) {
g1 = mp2[nums[i]];
g2 = i;
break;
}
mp2[nums[i]] = i;
}
}
if(g1 == -1 || g2 == -1) {
g1 = mp1[N/2];
g2 = mp2[N/2];
}
cout<<g1<<' '<<g2<<endl;
}
int main() {
cin>>P>>N;
if(P==1) p1();
else p2();
}
