// Use Switch case to implement the given conditions
function getLetter(s) {
    let letter;
    // Write your code here
    switch(s[0]){
        case ( 'a' || 'e' || 'o' || 'i' || 'u'):
                letter = 'A';
                break;
                
            case ('b' || 'c' || 'd' || 'f' || 'g'):
                letter = 'B';
                break;
                
            case ('h' || 'j' || 'k' || 'l' || 'm'):
                letter = 'C';
                break;
                
            case ('z' || 'n' || 'p' || 'q' || 'r' || 's' || 't' || 'v' || 'w' || 'x' || 'y' ):
                letter = 'D';
    }
    return letter;
}


function main() {
    const s = readLine();
    
    console.log(getLetter(s));
}