import java.util.*;
import java.lang.*;
import java.io.*;

class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner in = new Scanner(System.in);
		int n=in.nextInt();
		int m=in.nextInt();
		long[][] X = new long[100][100];
		String ans = new String("");
		for (int i=n-1; i>=0; i--){
			for (int j=0; j<m; j++)X[i][j]=in.nextLong();
		}
		for(int i=1;i<n;i++)X[i][0]=X[i][0]+X[i-1][0];
		for(int j=1;j<m;j++)X[0][j]=X[0][j]+X[0][j-1];
		for (int i=1; i<n; i++){
			for (int j=1; j<m; j++) X[i][j]=X[i][j]+Math.max(X[i - 1][j], X[i][j - 1]);
		}
		int k=n-1, t=m-1;
		while (k>0 || t>0){
			if (k>0 && t>0){
            			if (X[k-1][t]>X[k][t-1]){
            				ans+="F";
            				k--;
            			}
            			else{
            				ans+="R";
            				t--;    
            			}
			}
            		else if (k==0){
            			ans+="R";
            			t--;
			}
			else if (t==0){
            			ans+="F";
            			k--;
			}
		}
		String reverse = new StringBuffer(ans).reverse().toString();
		System.out.println(reverse);
	}
}