import string


def integerToLetter(i) -> str:
    """Returns letter sequence string for integer i."""
    # William Chapman, Jorj McKie, 2021-01-06

    ls = string.ascii_uppercase
    m = int((i - 1) / 26)  # how many times over
    n = (i % 26) - 1  # remainder
    str_t = ""
    for _ in range(0, m + 1):
        str_t = str_t + ls[n]
    return str_t