// dfmt off
T lread(T=long)(){return readln.chomp.to!T;}T[] lreads(T=long)(long n){return iota(n).map!((_)=>lread!T).array;}
T[] aryread(T=long)(){return readln.split.to!(T[]);}void arywrite(T)(T a){a.map!text.join(' ').writeln;}
void scan(L...)(ref L A){auto l=readln.split;foreach(i,T;L){A[i]=l[i].to!T;}}alias sread=()=>readln.chomp();
void dprint(L...)(lazy L A){debug{auto l=new string[](L.length);static foreach(i,a;A)l[i]=a.text;arywrite(l);}}
enum MOD=10^^9+7;alias PQueue(T,alias l="b<a")=BinaryHeap!(Array!T,l);import std;
// dfmt on

void main()
{
    auto T = sread();
    long N = T.length;
    auto ans = new char[](N);
    foreach (i; 0 .. N)
    {
        ans[i] = T[i];
        if (T[i] == '?')
        {
            if (0 < i && ans[i - 1] == 'P')
            {
                ans[i] = 'D';
                continue;
            }
            if (i < N - 1 && T[i + 1] == 'D')
            {
                ans[i] = 'P';
                continue;
            }
            if (i < N - 1 && T[i + 1] == '?')
            {
                ans[i] = 'P';
                continue;
            }
            ans[i] = 'D';
        }
    }
    writeln(ans);
}
