The magic number for the U.S. cities hoping to host the 2024 Olympics is $5 billion.

Boston, Los Angeles, San Francisco and Washington have all submitted spending plans under that mark for their bids to host the Olympics. Keeping the price tag down is a key goal of any future Olympic bid.

The U.S. Olympic Committee is less than two months away from deciding which city, if any, it will back as a candidate for the 2024 Games. The International Olympic Committee has put an emphasis on staying away from skyrocketing spending. It's an especially touchy subject in the United States, where, unlike most countries, the federal government does not help bankroll the Olympics.

None of the cities are offering specifics about their budgets, though all are coming in between $4 billion and $5 billion. Those numbers almost always grow after the Olympics are awarded. The preliminary budgets also don't include infrastructure improvements — airport expansions, highways, railways and the like — that often make the overall budget skyrocket.

"We've strongly encouraged each of the cities to make sure that whatever new infrastructure is needed in connection with the Games is part of the long-term plan for the city even if they don't host the Olympics," USOC CEO Scott Blackmun told The Associated Press.

Russia's total bill has been widely reported as $51 billion for the Sochi Games and China spent around $40 billion for the 2008 Olympics. Those numbers are part of the reason cities have grown more reluctant to get involved. The 2022 Winter Olympics has just two candidates, China and Kazakhstan.

Here's what to know about the United States' chances in the bid process:

THE DEADLINES:

The four cities will turn in the final pieces of their technical plans to the USOC in the next week. Some key dates to watch after that include the Dec. 16 USOC board meeting, where cities will give their official presentations to the board, then mid-January, which is the deadline the USOC has set for making a decision. The Games will be awarded in September 2017.

WHY A U.S. CITY MIGHT WIN:

So many factors point toward the United States hosting the 2024 Games. But the strongest may be that it's been 18 years and counting since the Summer Olympics have been on American soil. (The last U.S. Winter Games were 12 years ago.)

The USOC has worked hard to improve its standing among its international colleagues, and settling a financial dispute over how much money the USOC receives from TV and marketing rights was a big step toward that. The USOC doesn't like to play this card, but holding an Olympics in the most-successful Olympic country — the U.S. has won the most medals at the last five Summer Games — can't hurt. Exhibit A: NBC pays $7.75 billion through 2032 to televise the Games in America — a deal that dwarfs all the other international networks pay to televise in their respective countries.

WHY COULD A U.S. CITY LOSE:

IOC members love the money the U.S. brings to the movement, but some of them resent it, too. Publicly, many say they're happy the USOC leaders have become more a part of the family instead of lording power over them. "I think this is the best time for the States to come back with a nice bid," IOC member Sheikh Ahmad Al-Fahad Al-Sabah of Kuwait said recently. But the vote is secretive. Chicago (2016) and New York (2012) were both considered favorites at one point. Both lost badly, and "American arrogance" was brought up time and again. The USOC leadership has tried to tone that down by participating in more international meetings, and creating better relationships — both over a cocktail in the hotel lobby and during the tense negotiations in the meeting rooms. The ballot could be the answer to how successful they were.

CITIES IN THE MIX

Boston offers a great sports town with a compact Olympics. But it's small, and not great at big projects. (Remember the Big Dig?) Los Angeles has done it before and is full of Hollywood glamour, but also known for its sprawl. San Francisco offers great scenery, but it's pricey. Washington could offer expertise in security and lots of arenas and stadiums, but compares dimly to other world capitals that may compete, such as Paris and Rome.

GAME CHANGERS:

An African country has never hosted the Games. If one put together a solid bid it changes the calculus dramatically, much the way Rio's serious bid for 2016 helped doom Chicago. That's not planned now, but it's something to watch.

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Follow Eddie Pells on Twitter: http://twitter.com/epells