# Multiedges

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

A directed graph is given with a list of edges. Check whether it contains multiedges.

## Input

The first line contains number of vertices in a graph n (1 ≤ n ≤ 100) and number of edges m (1 ≤ m ≤ 10000). Each of the next m lines contains pair of integers - the edges of the graph.

## Output

Print YES if graph contains multiedges and NO otherwise.

## Examples

Input #1

Answer #1

Input #2

Answer #2

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