Time limit per test: 0.25 second(s) Memory limit: 65536 kilobytes

input: standard output: standard

Two cities A and B are connected by a straight road that is exactly l meters long. At the initial moment of time a cyclist starts moving from city A to city B at a speed v_{1} meters/second, and a pedestrian starts moving from city B to city A at a speed v_{2} meters/second. When one of them reaches a city, the road ends, so the person has to turn around and start moving in the opposite direction by the same road, keeping the original speed. As a result, the cyclist and the pedestrian are traveling between cities A and B indefinitely.

Your task is to calculate the number of times they will meet during the first t seconds. If they meet in exactly t seconds after the initial moment of time, this meeting should also be counted.

Input

The only line of input contains four integer numbers: l, v_{1}, v_{2} and t. All numbers are between 1 and 10^{9}, inclusively.

Output

Print a single integer — the number of times the cyclist and the pedestrian will meet during the first t seconds.