import sys

numA = numB = numC = numD = numF = 0

for grade in open(sys.argv[1], "r"):
    grade = int(grade)
    if (80 <= grade <= 100):
        numA += 1
    elif (65 <= grade < 80):
        numB += 1
    elif (55 <= grade < 65):
        numC += 1
    elif (50 <= grade < 55):
        numD += 1
    elif (0 <= grade < 50):
        numF += 1
    else:
        print grade, "is not a valid mark"

print "Grades: ", numA, "As /", numB, "Bs / ", numC, "Cs / ", \
      numD, "Ds / ", numF, "Fs / "