IT sounds like an Irish joke.
How many miles in a Dublin half-marathon?
The answer for a Huddersfield man and his two friends, fundraising for a hospital, turned out to be 26 miles and 385 yards - uncannily the same as a full marathon.
Father of two Richard Catling and his friends Ben Sweet and Greg Stubbs had looked forward to a jog on a 13-mile course through Dublin, after entering what they thought was a half-marathon to raise cash for St James's Hospital, Leeds.
But they found themselves lining up with 8,000 runners, many of them top athletes, in Dublin's annual marathon.
And having trained heavily overnight on pints of Guinness, it was a daunting prospect.
But the three managed to complete the course and raise about £1,500 for the hospital.
"It was too late to pull out when we finally found it was a marathon and not a half-marathon," said Richard, 37, of Netherton.
"We had travelled all the way to Dublin and had a lot of people sponsoring it so we thought we'd give it a go."
The three planned to raise money for the hospital where Richard's nine-year-old daughter Charlotte receives regular care.
Charlotte, who has a sister Rebecca, suffers from Crohn's disease, a chest condition and a blood disorder and expects to be in and out of hospital all her life.
Her dad teamed up with Ben, 25, formerly of Huddersfield but now living in Leeds, and Greg, 25, of Essex, to enter the race.
Richard said: "We didn't do much training. I train for football, as does Ben, and Greg is a fitness trainer so we were not completely unfit.
"None of the advance paperwork suggested it was anything other than a half marathon.
"We spent the weekend in Dublin enjoying the sights - and the Guinness - and it was only when we went to pre-register that we thought something was odd.
"There were people having massages, lots of stalls selling running gear and a very professional look about it all. We were handed the race map and realised we were in for a marathon.
"We talked about it and decided to give it a go, because people had backed us. Our intention was to reach 15 miles, where there was an ambulance stop, and then pull out.
"But once we started we all felt comfortable and we decided to carry on. We took it very steady but completed mile after mile, and we finished the entire race in 5 hours and 25 minutes.
"We were all very tired but it was worth it."
Richard's wife Sarah, who watched the race, said: "They looked shattered but did a great job.
"We want to thank everyone who has helped raise money for the hospital, who provide care for Charlotte and other children."