#include <bits/stdc++.h>
using namespace std;
 
int main(){
    long long n, x; cin >> n >> x;
 
    vector<pair<long long, long long>> a(n);
 
    for (long long i = 0; i < n; i++){
        cin >> a[i].first;
        a[i].second = i+1;
    }
 
    for (long long i = 0; i < n; i++){
        long long temp = x - a[i].first;
 
        long long l = 0;
        long long r = n-1;
 
        while (l < i && i < r){
            if (a[l].first + a[r].first == temp){ cout << a[l].second << ' ' << a[i].second << ' ' << a[r].second;
                return 0;
            }
            else if (a[l].first + a[r].first < temp){
                l++;
            }
            else r--;
        }
    }
 
    cout << "IMPOSSIBLE\n";
}

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