def vowel_count(string):
    vowels = "aeiou"
    No_of_vowels = 0
    for l in range(0,len(string)):
        character = string[l]
        for l in range(0,len(vowels)):
            if vowels[l] == character:
                No_of_vowels += 1

    return No_of_vowels

print(vowel_count("the quick brown fox jumps over the lazy dog"))