diff --git a/histogram.cpp b/histogram.cpp
index 4b8b614..ae048fb 100644
--- a/histogram.cpp
+++ b/histogram.cpp
@@ -1,5 +1,4 @@
 #include "histogram.h"
-
 void find_minmax(vector<double> vec, double& min, double& max) {
     min = vec[0];
     max = vec[0];
@@ -13,7 +12,6 @@ void find_minmax(vector<double> vec, double& min, double& max) {
         }
     }
 }
-
 vector<size_t> make_histogram(size_t number, vector<double> vec) {
     vector<size_t> bins(number);
     double mn, mx;
diff --git a/histogram_internal.h b/histogram_internal.h
new file mode 100644
index 0000000..819c07f
--- /dev/null
+++ b/histogram_internal.h
@@ -0,0 +1 @@
+void find_minmax(std::vector<double> vec, double& min, double& max);
diff --git a/main.cpp b/main.cpp
index f34eb01..af1c552 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,11 +1,9 @@
 #include "histogram.h"
 #include "text.h"
-
 struct Input {
     vector<double> vec;
     size_t korz{};
 };
-
 Input input_data() {
     Input in;
     size_t n, korz;
@@ -20,7 +18,6 @@ Input input_data() {
     cin >> in.korz;
     return in;
 }
-
 int main() {
     auto in = input_data();
     auto bins = make_histogram(in.korz, in.vec);