string

https://www.acwing.com/problem/content/4218/
#include<bits/stdc++.h
using namespace std;
int main()
{
    string s,cs;
    cs = "aeiouy";
    cin >> s;
    for(auto c : s)
    {
        c = tolower(c); //大写变为小写！
        if(cs.find(c) == -1) //找到返回第一次出现的下标，否则返回-1；
        {
            cout<<"."<<c;
        }
    }
    cout<<endl;
    return 0;
}