diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index 59f409d..548bdc9 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -87,11 +87,11 @@ function M.setup(user_config)
 	return config
 end
 
-local function default_filename(contest, problem_id, problem_letter)
-	local full_problem_id = problem_id:lower()
+local function default_filename(contest, contest_id, problem_id)
+	local full_problem_id = contest_id:lower()
 	if contest == "atcoder" or contest == "codeforces" then
-		if problem_letter then
-			full_problem_id = full_problem_id .. problem_letter:lower()
+		if problem_id then
+			full_problem_id = full_problem_id .. problem_id:lower()
 		end
 	end
 	return full_problem_id .. ".cc"
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index eae2965..5dc988b 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -31,7 +31,7 @@ local function setup_contest(contest_type)
 	logger.log(("set up %s contest environment"):format(contest_type))
 end
 
-local function setup_problem(problem_id, problem_letter)
+local function setup_problem(contest_id, problem_id)
 	if not vim.g.cp_contest then
 		logger.log("no contest mode set. run :CP <contest> first", vim.log.levels.ERROR)
 		return
@@ -52,7 +52,10 @@ local function setup_problem(problem_id, problem_letter)
 
 	vim.cmd("silent only")
 
-	local ctx = problem.create_context(vim.g.cp_contest, problem_id, problem_letter, config)
+	vim.g.cp_contest_id = contest_id
+	vim.g.cp_problem_id = problem_id
+
+	local ctx = problem.create_context(vim.g.cp_contest, contest_id, problem_id, config)
 
 	local scrape_result = scrape.scrape_problem(ctx)
 
@@ -128,7 +131,7 @@ local function run_problem()
 	local contest_config = config.contests[vim.g.cp_contest]
 
 	vim.schedule(function()
-		local ctx = problem.create_context(vim.g.cp_contest, problem_id, nil, config)
+		local ctx = problem.create_context(vim.g.cp_contest, vim.g.cp_contest_id, vim.g.cp_problem_id, config)
 		execute.run_problem(ctx, contest_config, false)
 		vim.cmd.checktime()
 	end)
@@ -152,7 +155,7 @@ local function debug_problem()
 	local contest_config = config.contests[vim.g.cp_contest]
 
 	vim.schedule(function()
-		local ctx = problem.create_context(vim.g.cp_contest, problem_id, nil, config)
+		local ctx = problem.create_context(vim.g.cp_contest, vim.g.cp_contest_id, vim.g.cp_problem_id, config)
 		execute.run_problem(ctx, contest_config, true)
 		vim.cmd.checktime()
 	end)
@@ -171,7 +174,7 @@ local function diff_problem()
 			return
 		end
 
-		local ctx = problem.create_context(vim.g.cp_contest, problem_id, nil, config)
+		local ctx = problem.create_context(vim.g.cp_contest, vim.g.cp_contest_id, vim.g.cp_problem_id, config)
 
 		if vim.fn.filereadable(ctx.expected_file) == 0 then
 			logger.log(("No expected output file found: %s"):format(ctx.expected_file), vim.log.levels.ERROR)
diff --git a/lua/cp/problem.lua b/lua/cp/problem.lua
index bc41175..2ae83a7 100644
--- a/lua/cp/problem.lua
+++ b/lua/cp/problem.lua
@@ -1,7 +1,7 @@
 ---@class ProblemContext
 ---@field contest string Contest name (e.g. "atcoder", "codeforces")
----@field problem_id string Raw problem ID (e.g. "abc123", "1933")
----@field problem_letter? string Problem letter for AtCoder/Codeforces (e.g. "a", "b")
+---@field contest_id string Contest ID (e.g. "abc123", "1933")
+---@field problem_id? string Problem ID for AtCoder/Codeforces (e.g. "a", "b")
 ---@field source_file string Source filename (e.g. "abc123a.cpp")
 ---@field binary_file string Binary output path (e.g. "build/abc123a")
 ---@field input_file string Input test file path (e.g. "io/abc123a.in")
@@ -12,19 +12,19 @@
 local M = {}
 
 ---@param contest string
----@param problem_id string
----@param problem_letter? string
+---@param contest_id string
+---@param problem_id? string
 ---@param config cp.Config
 ---@return ProblemContext
-function M.create_context(contest, problem_id, problem_letter, config)
+function M.create_context(contest, contest_id, problem_id, config)
 	local filename_fn = config.filename or require("cp.config").default_filename
-	local source_file = filename_fn(contest, problem_id, problem_letter)
+	local source_file = filename_fn(contest, contest_id, problem_id)
 	local base_name = vim.fn.fnamemodify(source_file, ":t:r")
 
 	return {
 		contest = contest,
+		contest_id = contest_id,
 		problem_id = problem_id,
-		problem_letter = problem_letter,
 		source_file = source_file,
 		binary_file = ("build/%s"):format(base_name),
 		input_file = ("io/%s.in"):format(base_name),
diff --git a/lua/cp/scrape.lua b/lua/cp/scrape.lua
index 8bf1fdc..b03a5c1 100644
--- a/lua/cp/scrape.lua
+++ b/lua/cp/scrape.lua
@@ -59,9 +59,9 @@ function M.scrape_problem(ctx)
 
 	local args
 	if ctx.contest == "cses" then
-		args = { "uv", "run", scraper_path, ctx.problem_id }
+		args = { "uv", "run", scraper_path, ctx.contest_id }
 	else
-		args = { "uv", "run", scraper_path, ctx.problem_id, ctx.problem_letter }
+		args = { "uv", "run", scraper_path, ctx.contest_id, ctx.problem_id }
 	end
 
 	local result = vim.system(args, {