vector<string> findWords(vector<string>& words) {
if(!(l[id].count(w[i]) ||l[id].count(w[i]+32) ) )
if(i==len) res.push_back(w);
vector<unordered_set<char>> l={\{'q','w','e','r','t','y','u','i','o','p'},{'a','s','d','f','g','h','j','k','l'},{'z','x','c','v','b','n','m'} };
// unordered_set<char> l1={'q','w','e','r','t','y','u','i','o','p'};
// unordered_set<char> l2={'a','s','d','f','g','h','j','k','l'};
// unordered_set<char> l3={'z','x','c','v','b','n','m'};
if(l[i].count(a) || l[i].count(a+32)) return i;
// cout<<l[1].count('h')<<endl;