// Python

def frequ(string s):
    i = 0
    freq = { }
    while i < len(s):
        C = tolower(s[i])
        freq[C]++
    
    return freq

// C++

unordered_map frequency (String s) {

	unordered_map<char, int> mp ;

	int i = 0 , n = s.length() ;

	for (i = 0 ; i < n ; i++) {

	    Char c = tolower (s(i))
	    mp[c]++ ;

	return mp ;
}