Shared code

/* 777 */
#include "bits/stdc++.h"
using namespace std;

#define int long long 
#define endl '\n'
using vi = vector <int>;
using vii = vector <vi>;
using pii = pair<int,int>;
using vpii = vector<pii>;
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(),x.end()
#define sortf(x) sort(all(x))
#define sortr(x) sort(all(x),greater<int>())

// const int MOD=1e9+7;
// const int inf=1e7;
vi vec;
// const int N=1e6;
int n;

void pre(){

}

void solve(){
	int x;cin>>n>>x;
	vpii pvec;
	for(int i=1;i<=n;++i){
		int temp;cin>>temp;
		pvec.eb(temp,i);
	}
	sortf(pvec);
	int l=0,r=n-1;
	while(l<r){
		int cur_sum=pvec[l].first+pvec[r].first;
		if(cur_sum==x){
			cout<<pvec[l].second<<" "<<pvec[r].second<<endl;
			return;
		}
		if(cur_sum<x)++l;
		else --r;
	}
	cout<<"IMPOSSIBLE"<<endl;
}

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	pre();
	solve();
}