#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+")