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
    while(line = await readline()){
        let set = new Set()
        for(let i of line) {
            if(0 <= i.charCodeAt() && i.charCodeAt() <= 127) {
                set.add(i)
            }
        }
        console.log(set.size)
    }
}()