grade(A,B,C,E,G) :- A>=5, A=<10,
					B>=5, B=<10,
					C>=5, C=<10,
					E>=1, E=<10,
					M is 3/((1/A)+(1/B)+(1/C)),
					M>E,
					F is (M+E)/2+(20/100*(M+E)/2),
					( F>=10 -> W is 10 ; W is F ),
					G is W.


grade(A,B,C,E,G) :- A>=5, A=<10,
					B>=5, B=<10,
					C>=5, C=<10,
					E>=1, E=<10,
					M is 3/((1/A)+(1/B)+(1/C)),
					M=<E,
					F is E+E*20/100,
					( F>=10 -> W is 10 ; W is F ),
					G is W.

grade(A,B,C,E,G) :- A>=1, A=<10,
					B>=1, B=<10,
					C>=1, C=<10,
					E>=1, E=<10,
					M is 3/((1/A)+(1/B)+(1/C)),
					M>E,
					G is (M+E)/2.

grade(A,B,C,E,G) :- A>=1, A=<10,
					B>=1, B=<10,
					C>=1, C=<10,
					E>=1, E=<10,
					M is 3/((1/A)+(1/B)+(1/C)),
					M=<E,
					G is E.

grade(A,B,C,E,G) :- G is 0.