#include <iostream>
#include <vector>
#include <algorithm>
#include <fstream>
using namespace std;

int main()
{
    int a;
    int b;
    cin >> a >> b;
    vector<int>v;
    vector<int>v2;

    for(int i=0; i<a; i++){
        int h;
        cin>>h;
        v2.push_back(h);
        v.push_back(h);
    }
    int i=0;
    int j=v.size()-1;

    sort(v.begin(),v.end());

    int a1=v[i];
    int b1=v[j];
    while(i<j){
    a1=v[i];
    b1=v[j];
    if(a1+b1==b){
        break;
    }
    if(a1 + b1 < b){
    i+=1;
    }
    else{
    j-=1;
    }
    }
    int brojac1=-1;
    int brojac2=-1;
    for(int i1=0; i1<v2.size(); i1++){
        if(v2[i1]==a1){
            brojac1=i1;
            break;
    }
    }
    for(int i = 0; i < v2.size(); i++) {
        if(v2[i] == b1 and i !=  brojac1) {
            brojac2 = i;
            break;
        }
    }
    if((a1 + b1 != b) or (brojac1==-1)or(brojac2==-1)){
        cout<<"IMPOSSIBLE";
        return 0;
    }
    cout<<brojac1 + 1<<" ";
    cout<<brojac2 + 1;
    return 0;
}