#!/usr/bin/python3

"""
Read a PAIRWISE maf from stdin and print the fraction of columns whose bases
match for each alignment.

TODO: generalize for more than two speceis.

usage: %prog < maf > out
"""

import sys

from bx.align import maf


def __main__():
    maf_reader = maf.Reader(sys.stdin)

    for m in maf_reader:
        match = 0
        total = 0
        for i in range(0, m.text_size):
            a = m.components[0].text[i].lower()
            b = m.components[1].text[i].lower()
            if a == b:
                match += 1
            total += 1

        print(match / total)


if __name__ == "__main__":
    __main__()