A. Nezha Naohai
time limit per test
1 second
memory limit per test
64 megabytes
input
standard input
output
standard output

Nezha caused conflicts due to the dominance of the Dragon Palace. In order to uphold justice and protect the people, Nezha caused three incidents in the sea. The specific process and outcome are as follows:

The 1st sea-tussle: Slayed the Yaksha Li Gen, took A hours;

The 2nd sea-tussle: Subdued Ao Bing, the third son of the Dragon King, took B hours;

The 3rd sea-tussle: Forced the Dragon King to submit, took C hours.

Nezha's disturbance in the sea would cause complaints. For every hour he causes trouble in the sea, he would generate D complaints. So, how many complaints did Nezha's disturbance in the sea cause in total?

Input

There are four integers $$$A$$$,$$$B$$$,$$$C$$$ and $$$D$$$ ($$$1 \le A,B,C,D \le 100$$$) respectively represent the time spent by Nezha in the sea for three times and the number of complaints caused by the sea disturbance per hour.

Output

The total number of complaints caused by Nezha's three disturbances in the sea.

Example
Input
1 2 3 4
Output
24