using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Numerics;
using System.Text;

namespace AtCoderWorkspace
{
    public class Solver
    {
        public void Solve()
        {
            var cin = new Scanner();
            var t = cin.next().ToCharArray();
            var ans = new StringBuilder();            
            if(t[0] == '?')
            {
                if(t.Length == 1)
                {
                    Console.WriteLine("D");
                    return;
                }
                if(t[1] == '?')
                {
                    t[0] = 'P';
                    t[1] = 'D';
                }
                else
                {
                    t[0] = 'D';
                }
            }

            var before = t[0];
            for (int i = 1; i < t.Length; i++)
            {                
                before = t[i-1];
                if(t[i] == '?')
                {
                    if (before == 'P')
                    {
                        t[i] = 'D';
                    }
                    else
                    {
                        if(i != t.Length - 1)
                        {
                            var after = t[i + 1];
                            if(after == 'D')
                            {
                                t[i] = 'P';
                            }
                            else{
                                if(after == '?')
                                {
                                    t[i] = 'P';
                                }
                                else
                                {
                                    t[i] = 'D';
                                }                                
                            }
                        }
                        else
                        {
                            t[i] = 'D';
                        }
                    }
                }
                
            }
            Console.WriteLine(new string(t));            
        }
    }

    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public int[] DPArrayInt(int N, int ex)
        {
            int[] Array = new int[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt();
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public long[] DPArrayLong(int N, int ex)
        {
            long[] Array = new long[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong();
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }

    class Program
    {
        static void Main(string[] s) => new Solver().Solve();
    }
}


Measured memory_bytes: 27480