#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <assert.h>
#include <array>
#include <cstdio>
#include <cstring>
#include <random>
#include <functional>
#include <numeric>
#include <bitset>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define minimize(a, x) a = std::min(a, x)
#define maximize(a, x) a = std::max(a, x)

typedef long long ll;
int const inf = 1<<29;

int main() {

  int c[5]; rep(i, 4) cin >> c[i+1];

  if(c[1] == 0) {
    if(c[2] == c[3] && c[3] == c[4] && c[4] == 0) {
      puts("R");
    }
    else {
      puts("I");
    }
  }
  else {
    if(c[1] * c[1] * (c[1] * c[3] - c[2] * c[2]) < 0) { puts("I"); }
    else { puts("R"); }
  }

  return 0;
}