Total Lights on the Ziggurat Levels

You are given an integer N representing the number of levels in a ziggurat. For each level i (1-indexed), you are provided with two integers, A_i and B_i. The number of lights that will be turned on in the i-th level is calculated using the formula:

$$A_i\times B_i^i$$

Your task is to compute the total number of lights that will be on across all levels of the ziggurat.

Example: For N = 3 and levels: (2, 3), (1, 2), (4, 1), the total number of lights is computed as:

$$2\times3^1 + 1\times2^2 + 4\times1^3 = 6+4+4 = 14$$

inputFormat

The first line contains a single integer N, the number of levels.

Each of the next N lines contains two space-separated integers A_i and B_i for the i-th level.

outputFormat

Output a single integer representing the total number of lights that are on across all levels of the ziggurat.

3
2 3
1 2
4 1

14