Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Metropolitan area | Country | Rank | Forstall\n2003 est. | Official population | Year |
| --- | --- | --- | --- | --- | --- |
| Ahmedabad | India |  |  | 6,352,254 | 2011 |
| Atlanta | United States |  |  | 5,457,831 | 2012 |
| Bangalore | India |  |  | 8,728,906 | 2011 |
| Barcelona | Spain |  |  | 5,357,422 | 2012 |
| Belo Horizonte | Brazil |  |  | 5,504,635 | 2012 |
| Beijing | China | 19 | 12,500,000 |  |  |
| Berlin | Germany |  |  | 5,097,712 | 2012 |
| Bogotá | Colombia |  |  | 9,023,644 | 2014 |
| Buenos Aires | Argentina | 17 | 13,170,000 | 12,801,364 | 2010 |
| Cairo | Egypt | 16 | 14,450,000 |  |  |
| Chennai | India |  |  | 8,917,749 | 2011 |
| Chicago | United States |  | 9,175,000 | 9,522,434 | 2012 |
| Dallas–Fort Worth | United States |  |  | 6,700,991 | 2012 |
| Delhi | India | 8 | 18,600,000 | 21,753,486 | 2011 |
| Dhaka | Bangladesh |  |  | 12,797,394 | 2008 |
| Houston | United States |  |  | 6,177,035 | 2012 |
| Hyderabad | India |  |  | 7,749,334 | 2011 |
| İstanbul | Turkey |  |  | 14,160,467 | 2014 |
| Jakarta | Indonesia | 6 | 18,900,000 | 28,019,545 | 2010 |
| Karachi | Pakistan | 20 | 11,800,000 |  |  |
| Kolkata | India | 14 | 15,100,000 | 14,617,882 | 2011 |
| Lima | Peru |  |  | 9,735,587 | 2014 |
| London | United Kingdom | 18 | 12,875,000 | 13,614,409 | 2012 |
| Los Angeles | United States | 13 | 15,250,000 | 13,052,921 | 2012 |
| Madrid | Spain |  |  | 6,387,824 | 2012 |
| Manila | Philippines | 11 | 16,300,000 | 11,855,975 | 2010 |
| Mexico City | Mexico | 3 | 20,450,000 | 20,116,842 | 2010 |
| Miami | United States |  |  | 5,762,717 | 2012 |
| Moscow | Russia | 15 | 15,000,000 | 17,000,000 |  |
| Mumbai | India | 5 | 19,200,000 | 20,748,395 | 2011 |
| Nagoya | Japan |  |  | 9,107,000 | 2010 |
| New York | United States | 4 | 19,750,000 | 19,831,858 | 2012 |
| Osaka-Kobe-Kyoto (Keihanshin) | Japan | 9 | 17,375,000 | 19,342,000 | 2010 |
| Paris | France |  |  | 12,223,100 | 2010 |
| Philadelphia | United States |  |  | 6,018,800 | 2012 |
| Pune | India |  |  | 5,049,968 | 2011 |
| Ruhr | Germany |  |  | 5,135,136 | 2012 |
| Rio de Janeiro | Brazil |  |  | 11,846,530 | 2012 |
| São Paulo | Brazil | 7 | 18,850,000 | 19,956,590 | 2012 |
| Santiago | Chile |  |  | 6,683,852 | 2012 |
| Shanghai | China | 10 | 16,650,000 |  |  |
| Seoul | South Korea | 2 | 20,550,000 | 25,721,000 | 2012 |
| Singapore | Singapore |  |  | 5,312,000 | 2012 |
| Tokyo | Japan | 1 | 32,450,000 | 36,923,000 | 2010 |
| Toronto | Canada |  |  | 5,583,064 | 2011 |
| Washington, D.C. | United States |  |  | 5,860,342 | 2012 |
Question:
how many cities are in the united states?
Answer:
9