Sanalista

const readline = require('readline');

const r = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    terminal: false
});
function doubles(str){
    let foundletters=[];
    for(let i of str) {
        if(foundletters.includes(i)){
            foundletters.splice(foundletters.indexOf(i),1);
        }
        else{
            foundletters.push(i);
        }
    }
    return Number(foundletters==[])
}
const lines = r.readline(1)
let workinglines;
for(let i = 0; i<lines; i++){
    workinglines += Number(doubles(String(r.readline(i+1))));
}
console.log(workinglines);

Test 1

Verdict: RUNTIME ERROR

/box/input/code.js:20
const lines = r.readline(1)
                ^

TypeError: r.readline...

Test 2

Verdict: RUNTIME ERROR

/box/input/code.js:20
const lines = r.readline(1)
                ^

TypeError: r.readline...

Test 3

Verdict: RUNTIME ERROR

/box/input/code.js:20
const lines = r.readline(1)
                ^

TypeError: r.readline...