"use strict"
function main(arg) {
    let data = arg.trim().split("\n")[0].split("")
    for (let i = 0; i < data.length; i++) {
        if (data[i] !== '?') continue
        if (data[i] === '?') {
            data[i] = 'D'
        }
        if (data[i] === '?') {
            data[i] = 'D'
        }
    }
    data = data.join("")
    // let pd = data.split("PD").length - 1
    // let d = data.split("D").length - 1
    // console.log(pd + d)
    console.log(data)
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));