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).

Input: Consider Input: Solve -2*i = -4*x + 1 - 17, 5*i = 5*x + 20 for i.

Output: 0


Input: Consider Input: Suppose -6 = -t - 2*t. Suppose 4*h - 10 = -t*r, -h - 3*h + 3*r + 5 = 0. Suppose 19 + 15 = h*g. What is the greatest common divisor of g and 153?

Output: 17


Input: Consider Input: What is next in -841, -842, -843, -844, -845?


Output: -846