#include <iostream>
using namespace std;
int main() {
    long c1, c2, c3, c4;
    scanf("%ld%ld%ld%ld", &c1, &c2, &c3, &c4);
    puts(((c1 * c4 - c2 * c3) * (c1 * c4 - c2 * c3) - 4 * (c2 * c4 - c3 * c3) * (c1 * c3 - c2 * c2) >= 0) ? "R" : "I");
    return 0;
}