Vicente Fox was the president of Mexicofor six years, starting in 2000.He says Donald Trump should not insult Mexicansduring his campaign for the Republican Party's presidential nomination.Trump says he will build a wall between the United States and Mexico.And he says he will get Mexico to pay for it if he becomes president.People think the cost of the wall could be greater than $1 billion.Trump also says he plans to deport Mexicanswho are not in the U.S. legally.He also wants to deport childrenborn to undocumented immigrants in the U.S.In response to Trump's claims,Fox recently told Fusion TV:"I'm not going to pay for that wall."An expletive is a curse or swear word.Fox says he is surprised Trump won the votesof 46 percent of the Hispanicswho voted in the recent Nevada caucus.Felipe Calderon followed Fox as Mexico's president.They both say they are concerned about the anti-Mexican sentimentTrump is stirring up.Calderon told The Washington Postthe wall would be "useless"and said "we won't pay a cent for that stupid wall."Calderon also noted that Trump is ignoring recent statisticsfrom the Pew Research Centerthat show more Mexicans are returning homethan entering the United Statesin the five years ending in 2014.Calderon says the fact that Trump is ignoring those statisticsshows that he is "an ignorant man."Trump responded to Fox's comments,using Twitter to say that the former presidentshould apologize for using bad language.Fox says he will not apologize."He's the one who should apologize," Fox says.