let strAry = [];

for (let i = 0; i < 3000; i++) {
  let str = "";
  for (let j = 0; j < 10; j++) {
    str += String.fromCharCode(97 + Math.floor(Math.random() * 26));
  }
  strAry.push(str);
}
let strSet = new Set(strAry);

let lookups = [];
for (let i = 0; i < 20; i++) {
  lookups.push(strAry[Math.floor(Math.random() * strAry.length)]);
}

let out = "";