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A. Fashion in Berland

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputAccording to rules of the Berland fashion, a jacket should be fastened by all the buttons except only one, but not necessarily it should be the last one. Also if the jacket has only one button, it should be fastened, so the jacket will not swinging open.

You are given a jacket with *n* buttons. Determine if it is fastened in a right way.

Input

The first line contains integer *n* (1 ≤ *n* ≤ 1000) — the number of buttons on the jacket.

The second line contains *n* integers *a*_{i} (0 ≤ *a*_{i} ≤ 1). The number *a*_{i} = 0 if the *i*-th button is not fastened. Otherwise *a*_{i} = 1.

Output

In the only line print the word "YES" if the jacket is fastened in a right way. Otherwise print the word "NO".

Examples

Input

3

1 0 1

Output

YES

Input

3

1 0 0

Output

NO

Codeforces (c) Copyright 2010-2017 Mike Mirzayanov

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