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
    //let obj = {}
    while(line = await readline()){
        // for(let i = 0; i < line.length; i++) {
        //     let char = line[i]
        //     let code = char.charCodeAt()
        //     if (code >= 0 && code <= 127) {
        //         if (obj[char]) {
        //             obj[char]++
        //         } else {
        //             obj[char] = 1
        //         }
        //     }
        // }
        let arr = line.trim().split('')
        let mySet = new Set(arr)
        console.log(mySet.size)

    }
    // console.log(Object.keys(obj).length)
}()