Given a simple high-school level math question, you are required to solve it and provide the final answer. The final answer is always a single number. These questions can range from a variety of topics like simple arithmetic, solving equations, converting a quantity from one unit to another, finding remainders/GCD/LCM, finding probabilities etc. Each question has only one correct answer. This answer can be a positive or negative integer, a fraction or a decimal number. If the answer is a negative number use the hyphen (e.g. -42) symbol for the minus sign. For decimal numbers, do not add extra zeros after the decimal point. For fractional numbers, separate the numerator and denominator using a forward slash (e.g. 3/25).

Ex Input:
Two letters picked without replacement from {t: 1, z: 1, v: 1, b: 1, s: 1, p: 2}. What is prob of picking 1 t and 1 p?

Ex Output:
2/21


Ex Input:
Two letters picked without replacement from {i: 3, v: 2}. Give prob of sequence iv.

Ex Output:
3/10


Ex Input:
Suppose -f - 1 + 2 = 0. Solve -5*s + b = -s - f, 3*b + 19 = -4*s for s.

Ex Output:

-1