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# System prepended metadata

title: Untitled

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#python 作業 410711224呂浩丞
a=input()
a=int(a)
if a<=50:
    print("E")
elif a<=59:
    print("D")
elif a<=62:
    print("c-")
elif a<=66:
    print("c")
elif a<=69:
    print("c+")
elif a<=72:
    print("B-")
elif a<=76:
    print("B")
elif a<=79:
    print("B+")
elif a<=84:
    print("A-")
elif a<=89:
    print("A")
else :
    print("A+")
