import std;

void main() {
    string s = read;
    foreach (c; s) {
        if (c == '?') write('D');
        else write(c);
    }
    writeln();
}

void scan(T...)(ref T a) {
    string[] ss = readln.split;
    foreach (i, t; T) a[i] = ss[i].to!t;
}
T read(T=string)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readints = reads!int;
