YES(?, a^2 + 3*a + 2)

Initial complexity problem:
1:	T:
		(1, 1)    f1(a, b) -> f3(a, a) [ a >= 1 ]
		(?, 1)    f3(a, b) -> f3(a, b - 1) [ b >= 1 ]
		(?, 1)    f3(a, b) -> f3(a - 1, a - 1) [ 0 >= b /\ a >= 2 ]
	start location:	f1
	leaf cost:	0

A polynomial rank function with
	Pol(f1) = V_1 + 1
	Pol(f3) = V_1 + 1
orients all transitions weakly and the transition
	f3(a, b) -> f3(a - 1, a - 1) [ 0 >= b /\ a >= 2 ]
strictly and produces the following problem:
2:	T:
		(1, 1)        f1(a, b) -> f3(a, a) [ a >= 1 ]
		(?, 1)        f3(a, b) -> f3(a, b - 1) [ b >= 1 ]
		(a + 1, 1)    f3(a, b) -> f3(a - 1, a - 1) [ 0 >= b /\ a >= 2 ]
	start location:	f1
	leaf cost:	0

A polynomial rank function with
	Pol(f3) = V_2
and size complexities
	S("f3(a, b) -> f3(a - 1, a - 1) [ 0 >= b /\\ a >= 2 ]", 0-0) = a
	S("f3(a, b) -> f3(a - 1, a - 1) [ 0 >= b /\\ a >= 2 ]", 0-1) = a
	S("f3(a, b) -> f3(a, b - 1) [ b >= 1 ]", 0-0) = a
	S("f3(a, b) -> f3(a, b - 1) [ b >= 1 ]", 0-1) = a
	S("f1(a, b) -> f3(a, a) [ a >= 1 ]", 0-0) = a
	S("f1(a, b) -> f3(a, a) [ a >= 1 ]", 0-1) = a
orients the transition
	f3(a, b) -> f3(a, b - 1) [ b >= 1 ]
weakly and the transition
	f3(a, b) -> f3(a, b - 1) [ b >= 1 ]
strictly and produces the following problem:
3:	T:
		(1, 1)            f1(a, b) -> f3(a, a) [ a >= 1 ]
		(a^2 + 2*a, 1)    f3(a, b) -> f3(a, b - 1) [ b >= 1 ]
		(a + 1, 1)        f3(a, b) -> f3(a - 1, a - 1) [ 0 >= b /\ a >= 2 ]
	start location:	f1
	leaf cost:	0

Complexity upper bound a^2 + 3*a + 2

Time: 0.189 sec (SMT: 0.180 sec)