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

int main() {
    int a, b, c;
    cin >> a >> b >> c;

    if ((a >= b + c) || (b >= a + c) || (c >= a + b)) {
        cout << "impossible";
        return 0;
    }

    if ((c*c == a*a + b*b) || (a*a == b*b + c*c) || (b*b == a*a + c*c)) {
        cout << "right";
        return 0;
    }

    if (c < a) swap(c, a);
    if (c < b) swap(c, b);
    if (b < a) swap(a, b);

    if (c*c < a*a + b*b) {
        cout << "acute";
        return 0;
    } else {
        cout << "obtuse";
        return 0;
    }
}