#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef complex<double> P;
typedef pair<int,int> pii;
#define REP(i,n) for(ll i=0;i<n;++i)
#define REPR(i,n) for(ll i=1;i<n;++i)
#define FOR(i,a,b) for(ll i=a;i<b;++i)

#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define DEBUG_VEC(v) cout<<#v<<":";REP(i,v.size())cout<<" "<<v[i];cout<<endl
#define ALL(a) (a).begin(),(a).end()

#define MOD (ll)(1e9+7)
#define ADD(a,b) a=((a)+(b))%MOD
#define FIX(a) ((a)%MOD+MOD)%MOD

#define EPS 1e-9

int main(){
  double c1,c2,c3,c4;
  cin>>c1>>c2>>c3>>c4;
  // X = z1+z2
  // Y = z1z2
  double X = (c1*c4-c2*c3) / (c1*c3-c2*c2);
  double Y = (c2*c4-c3*c3) / (c1*c3-c2*c2);
  // if imag: X = 2*a, Y = a^2 + b^2
  double a = X/2.0;
  if(Y - a*a > 0){
    cout << "I" << endl;
  }else{
    cout << "R" << endl;
  }
  return 0;
}