#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>
#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define var auto
#define mod 1000000007
#define inf 2147483647
#define nil -1
#define mp make_pair
typedef long long ll;
using namespace std;

template <typename T>
inline void output(T a, int p) {
    if(p){
        cout << fixed << setprecision(p)  << a << "\n";
    }
    else{
        cout << a << "\n";
    }
}
// end of template

ll p2(ll a){
    return a * a;
}

int main() {
    cin.tie(0);
    // source code
    ll c1, c2, c3, c4;
    cin >> c1 >> c2 >> c3 >> c4;
    
    ll ret = (c1 * c3 - p2(c2)) * (p2(c1 * c4 - c2 * c3) - 4 * (c2 * c4 - p2(c3) * (c1 * c3 - p2(c2))));
    
    cout << ((ret >= 0) ? "R" : "I") << endl;
    return 0;
}