#include <iostream>
typedef long long ll;
using namespace std;
int main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    // source code
    ll c1, c2, c3, c4;
    cin >> c1 >> c2 >> c3 >> c4;
    cout << (((c1 * c4 - c2 * c3) * (c1 * c4 - c2 * c3) - 4 * (c2 * c4 - c3 * c3) * (c1 * c3 - c2 * c2) >= 0) ? "R" : "I") << "\n";
    return 0;
}