题解 | #字符个数统计#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    const list = []
    while(line = await readline()){
       list.push(line)
    }
    console.log(new Set(...list).size)
}()