개발야옹

https://www.acmicpc.net/problem/1316

const fs = require('fs');
const input = fs.readFileSync('/dev/stdin').toString().split("\n");

const N = Number(input[0]);
let answer = 0;

for(let i = 0 ; i < N ; i++) {
    let cnt = 0;
    let view = [];
    const tmp = input[i+1].split("");
    let prev = '';
    tmp.forEach((t, index) => {
        if(index === 0) prev = t;
        if(prev !== t && !view.includes(t)) {
            view.push(prev);
            prev = t;
        }
        if(view.includes(t)) {
            cnt++;
        }
    });
    if(cnt > 0) answer++; 
}

console.log(N-answer);