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C. A Piece of Cake

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputHow to make a cake you'll never eat.

Ingredients.

- 2 carrots
- 0 calories
- 100 g chocolate spread
- 1 pack of flour
- 1 egg

Method.

- Put calories into the mixing bowl.
- Take carrots from refrigerator.
- Chop carrots.
- Take chocolate spread from refrigerator.
- Put chocolate spread into the mixing bowl.
- Combine pack of flour into the mixing bowl.
- Fold chocolate spread into the mixing bowl.
- Add chocolate spread into the mixing bowl.
- Put pack of flour into the mixing bowl.
- Add egg into the mixing bowl.
- Fold pack of flour into the mixing bowl.
- Chop carrots until choped.
- Pour contents of the mixing bowl into the baking dish.

Serves 1.

Input

The only line of input contains a sequence of integers *a*_{0}, *a*_{1}, ... (1 ≤ *a*_{0} ≤ 100, 0 ≤ *a*_{i} ≤ 1000 for *i* ≥ 1).

Output

Output a single integer.

Examples

Input

4 1 2 3 4

Output

30

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