total length of the streets

I am a volunteer of the cultural public non-commercial project "Тарас шевченко єднає народи" ("Taras Shevchenko unites the people"). I was asked to calculate the total length of objects with the name "Shevchenko" in Ukraine. I need to write a program that:

1. Make a complete list of settlements in Ukraine and put them in a table.
2. In each locality will compile a list of linear objects with the name "Shevchenko" (streets, lanes, boulevards, avenues, highways, alleys) and put them in a table.
3. For each such object will find the nodes of the object and put them in a table.
4. For each such object, calculate the length of the object and add to the table.
5. Sum all the resulting lengths.

I would be grateful for an explanation of how to find the necessary data in the OSM file, as well as for explaining the structure of the OSM file. I would be grateful for any help in writing up such a program. I will also be grateful for the help in finding similar programs.