function solution(skill, skill_trees) {
function isCorrect(n) {
let test = skill.split('');
for (var i = 0; i < n.length; i++) {
if (!skill.includes(n[i])) continue;
if (n[i] === test.shift()) continue;
return false;
}
return true;
}
return skill_trees.filter(isCorrect).length;
}