def IndexOfNth(s, value, n):
    """Gets the index of Nth occurance of a given character in a string.

    :param str s: Input string
    :param char value: Input char to be searched.
    :param int n: Nth occurrence of char to be searched.
    :return: Index of the Nth occurrence in the string.
    :rtype: int
    """
    remaining = n
    for i, elt in enumerate(s):
        if elt == value:
            remaining -= 1
            if remaining == 0:
                return i
    return -1