user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: What's the subject of the picture, Mt St Helens? 
Knowledge Triplets: North America, location.location.partially_contains, United States of America
Skamania County, location.location.containedby, Washington
United States of America, location.location.partially_containedby, North America
Cascade Range, location.location.contains, Mount St. Helens
Washington, base.aareas.schema.administrative_area.administrative_parent, United States of America
Washington, base.biblioness.bibs_location.country, United States of America
Alleyne FitzHerbert, 1st Baron St Helens, symbols.name_source.namesakes, Mount St. Helens
Skamania County, location.administrative_division.second_level_division_of, United States of America
United States of America, base.biblioness.bibs_topic.subsumes, United States of America
Mount St. Helens, location.location.containedby, North America
United States of America, base.locations.countries.states_provinces_within, Washington
Mount St. Helens, geography.mountain.mountain_type, Stratovolcano
Mount St. Helens, common.image.appears_in_topic_gallery, Mount St. Helens
United States of America, location.country.administrative_divisions, Washington
Mount St. Helens, location.location.containedby, Cascade Range
Washington, location.administrative_division.country, United States of America
Spirit Lake, location.location.containedby, Mount St. Helens
Mount St. Helens, common.topic.image, Mt St Helens
Mt St Helens, common.image.appears_in_topic_gallery, Mount St. Helens
Thomas J. Dryer, people.person.nationality, United States of America
Washington, location.administrative_division.first_level_division_of, United States of America
Mount St. Helens, location.location.contains, Spirit Lake
United States of America, location.location.primarily_containedby, North America
Mt St Helens, common.image.size, m.022pw9_
Spirit Lake, location.location.containedby, United States of America
Skamania County, location.location.contains, Mount St. Helens
Mount St. Helens, common.topic.notable_for, g.125byqbyq
Mount St. Helens, common.topic.image, Mount St. Helens
United States of America, base.biblioness.bibs_topic.is_really, United States of America
Spirit Lake, geography.lake.basin_countries, United States of America
Mount St. Helens, geography.mountain.mountain_type, Volcano
Mount St. Helens, symbols.namesake.named_after, Alleyne FitzHerbert, 1st Baron St Helens
Mount St. Helens, geography.mountain.mountain_range, Cascade Range
Mount St. Helens, location.location.containedby, Washington
Thomas J. Dryer, geography.mountaineer.first_ascents, Mount St. Helens
United States of America, location.location.partially_contains, Cascade Range
Mount St. Helens, location.location.containedby, United States of America
Mount St. Helens, geography.mountain.first_ascenders, Thomas J. Dryer
Cascade Range, location.location.partially_containedby, Washington
United States of America, base.locations.countries.continent, North America
Washington, location.location.partially_contains, Cascade Range
Washington, base.locations.states_and_provences.country, United States of America
Mount St. Helens, common.topic.notable_types, Mountain
Mount St. Helens, location.location.containedby, Skamania County
Mount St. Helens, geography.mountain.mountain_type, Stratovolcano
Mount St. Helens, geography.mountain.mountain_type, Volcano
Mount St. Helens, location.location.geolocation, m.05kgc0h
North America, location.location.contains_major_portion_of, United States of America
Mount St. Helens, location.location.contains, Crater Glacier
Mt St Helens, common.image.appears_in_topic_gallery, Mount St. Helens
United States of America, location.country.first_level_divisions, Washington
Cascade Range, location.location.partially_containedby, United States of America
Mount St. Helens, common.topic.article, m.094y8
Crater Glacier, location.location.containedby, Washington
United States of America, base.aareas.schema.administrative_area.administrative_children, Washington
Mount St. Helens, location.location.events, 1980 eruption of Mount St. Helens
North America, base.locations.continents.countries_within, United States of America
1980 eruption of Mount St. Helens, time.event.locations, Mount St. Helens
Washington, location.location.containedby, United States of America
Cascade Range, location.location.containedby, North America
Crater Glacier, location.location.containedby, Mount St. Helens

Answer: Stratovolcano
Volcano