const readline= require('readline'); const rl= readline.createInterface({ input: process.stdin, output: process.stdout, terminal:false }); const userInput=[]; rl.on("line", (data)=>{ userInput.push(data); }); rl.on('close', ()=>{ console.log(firstNotRepeatingCharacter(userInput[0])); }) function firstNotRepeatingCharacter(s) { for (let i = 0; i < s.length; i++) { if(s.indexOf(s.charAt(i)) == s.lastIndexOf(s.charAt(i))) { return s.charAt(i) } } return }