Description

Computers are connected in a company network. When computer 1 gets infected with a virus, it spreads to all connected computers. Find the number of computers infected through computer 1. (Exclude computer 1 itself)

Input

Output

Constraints

• •1 <= N <= 100
• •1 <= M <= N*(N-1)/2
• •Connections are bidirectional

Examples

7
6
1 2
2 3
1 5
5 2
5 6
4 7

4