๐จ ์ฐธ๊ณ ์ฝ๋
๐จ ์ฐธ๊ณ ์ค๋ช
์ฝ๋
const fs = require('fs');
const input = fs.readFileSync('/dev/stdin').toString().trim().split('\n').map(Number);
const G = input.shift();
const P = input.shift();
const parents = new Array(G + 1).fill(0).map((el, index) => index);
const find = (index) => {
if (index === parents[index]) return index;
return (parents[index] = find(parents[index]));
};
let count = 0;
for (let i = 0; i < P; i++) {
const g = input[i];
if (!find(g)) break;
count++;
parents[find(g)] = find(find(g) - 1);
}
console.log(count);