Windy Weather 3#5723
Piglet was lying on the meadow, watching the blades of grass sway. He noticed that the swaying was caused by the wind and came up with a method to measure the wind's strength using the grass blades. According to Piglet's definition, the wind's strength is determined by the number of groups of grass blades with different heights. If there is only one such group, Piglet considers it a perfectly calm day, meaning there is no wind, and the wind's strength is zero.
The first line contains a single number - the number of grass blades Piglet is observing. The second line contains numbers separated by spaces - the heights of these grass blades.
All input numbers are natural numbers that do not exceed , as Piglet preferred not to count much and had never encountered numbers greater than in his life.
Output a single number - the strength of the wind according to Piglet's definition.
Example 1