import std.stdio;
import std.algorithm;
import std.math;
import std.conv;
import std.string;

T readNum(T)(){
  return readStr.to!T;
}

T[] readNums(T)(){
  return readStr.split.to!(T[]);
}

string readStr(){
  return readln.chomp;
}

void main(){
  auto t = readStr;
  auto s = t.replace("?", "D");

  writeln(s);
}
