#include <bits/stdc++.h>
using namespace std;
#define ll long long
void solve(int tc)
{
int t, n;
cin>>t>>n;
vector<int> a(n), cnt(t, 0);
for(auto &i : a) {
cin>>i;
++cnt[i];
}
if(n <= 5000) {
pair<int, int> p = {-1, -1};
int tot = n - t;
for(int i=0;i<n;++i) {
int tot2 = 0;
vector<int> cnt2(t, 0);
for(int j=i;j<n;++j) {
if(cnt[a[j]] > 1) {
++tot2;
if(tot2 == tot) {
if(p.first == -1 || p.second - p.first + 1 > j - i + 1) {
p = {i, j};
}
}
}
--cnt[a[j]];
++cnt2[a[j]];
}
for(int i=0;i<t;++i)
cnt[i] += cnt2[i];
}
cout<<p.first<<' '<<p.second<<'\n';
} else {
int tot = n - t, nn = 0;
pair<int, int> p = {-1, -1};
deque<int> p3;
deque<pair<int, int>> p2;
vector<int> cnt2(t, 0);
for(int i=0;i<n;++i) {
++cnt2[a[i]];
p2.push_back({a[i], cnt2[a[i]]});
p3.push_back(i);
if(cnt2[a[i]] == 1)
++nn;
while(p2.size() > 0 && p2[0].second == 1 && cnt2[p2[0].first] == cnt[p2[0].first]) {
p2.pop_front();
p3.pop_front();
}
if(nn >= tot && p3.size()) {
int gg = i - p3.front() + 1;
if(p.first == -1 || p.second - p.first + 1 > gg) {
p = {p3.front(), i};
}
}
}
cout<<p.first<<' '<<p.second<<'\n';
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
// freopen("problem.in", "r", stdin);
// freopen("problem.out", "w", stdout);
int t = 1;
// cin >> t;
for (int i = 1; i <= t; ++i) {
solve(t - i);
}
return 0;
}
