Intimidated by long queues outside the Egyptian embassy visa office? Puzzled by the visa form? Then head for the neem tree.
Beneath the fine-leafed tree, a few dusty metres from Khartoum's colonial-era Egyptian consular building, is the "office" where Mustafa Ali and his convivial cohorts have for years dispensed their wisdom.
Their briefcases filled with documents and staplers serve both as a toolbox and a desk for these self-employed clerks as they help travellers fill out their visa papers for an average of five pounds (about $1).
"We have no office. We have nothing," says Bashir Dahab (62) one of four in the group. They have all travelled the region, working other jobs, before retiring and ending up back here, under the neem tree.
"We help people and at the same time it is our life. Our salary is from these forms," Dahab says.
Not that the daily salary is anything to rely on.
"Sometimes five pounds. Sometimes 50 pounds. Sometimes nothing," says Dahab who, like his colleague Ali, can serve clients in English as well as Arabic.
The goateed, bespectacled Dahab even knows a little French, learned in the early 1970s when he studied at what was then Cairo University's branch in Khartoum.
But their daily gathering is not only about work. It is a chance to get out of the house and chat, as other men might do at a cafe.
"Because when you are at home the wife asks you: 'Bring chicken ... bring oil' ... and so on and so on," says Dahab, whose business card features sunset-silhouetted date palms emblematic of his native Nubia, in northern Sudan.
So they sit under the tree on chairs they brought themselves, talking, reading newspapers and exchanging greetings with passers-by on Al-Gamhuria Street, a three-lane main thoroughfare in the crumbling, garbage-strewn heart of Khartoum.
'He knows how to do it very well'
Ali (50) eagerly expounds on a range of topics from African culture to religion, history and languages, a reflection of the primary school teacher he was for many years.
He took up the visa trade about 13 years ago, following the lead of his relative, "Mr Jaafer", who has a year's additional seniority.
"He's our boss," jokes Ali, balding and with a moustache.
Jaafer has big glasses, a big smile and a big stomach. He leans back in his chair, places some prayer beads around his neck, and rests his bare feet on the broken tank of a toilet.
This is Ramadan, when the queues at the embassy shorten and there is less business for Jaafer and the others.
"You can say it's dead season," Dahab says, in contrast to May and June when many Sudanese holiday in neighbouring Egypt, which ruled Sudan with Britain until 1956.
The fourth member of the group, known as Abu Digin for his grey-flecked black beard and moustache, is a native of oil-rich Heglig on Sudan's southern border. He worked in Saudi Arabia before joining Dahab and the others about seven years ago - his trade signalled by the pen in his breast pocket.
The clerks say people are doing similar jobs outside other embassies, government offices and courts in the country, which has a 62 percent literacy level, according to the United Nations.
After years in the business, the visa clerks have developed a reputation.
"I heard his name," says Mohammed Adam Ahmad (25) who walked determinedly towards Ali after first stopping at the old stone embassy building.
"Because he knows how to do it very well," says Ahmad, a Ghanaian studying Arabic in Sudan. He wants a visa in order to holiday in Egypt during his school break.
Ahmad stands and waits, ready to answer Ali's questions as he completes the form.
A warm wind filled with sand rustles the neem tree, a species which Ali says was introduced to Sudan from Asia by the British.
When the single-page form is complete, Ali motions for Ahmad to sign it with a fat yellow pen. Then the student hands over two small photos, which Ali staples to the application along with a photocopy from his passport.
The job done, Ahmad pays four pounds.
A reporter asks if he is satisfied with the service.
"Yeah," he smiles, and heads back to the embassy, his journey now a little bit closer thanks to the men under the neem tree.