# The presents to the 8th of March

# The presents to the 8th of March

Boys decided to prepare presents for girls on a holiday of **8**th of March. When they were preparing presents, they quickly put there a congratulation postcard and a soft toy. But when they began to put mandarins, they came face to face with such trouble. At first they wanted to put **m** mandarins in every package (and in other packages - apples), but they couldn't do it because in one package were **m** - **1** mandarins. Then they decided to put **m** - **1** mandarins, but **m** - **2** mandarins left. Then they decided to put **m** - **2** mandarins, but **m** - **3** mandarins left, and so on. When they decide to put **2** mandarins, then **1** mandarin left. How many mandarins did the boys buy?

#### Input

The number of mandarins **m** (**1** < **m** ≤ **1000**), that the boys wanted to put initially into the presents.

#### Output

The minimum possible number of mandarins, that the boys bought as a gift for the girls.

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