diff --git a/lab2_1.c b/lab2_1.c
new file mode 100644
index 0000000..ee24fc8
--- /dev/null
+++ b/lab2_1.c
@@ -0,0 +1,21 @@
+int sum_to_n(int n) {
+  int sum = 0;
+  for (int i = 1; i <= n; i++) {
+    sum += i;
+  }
+  return sum;
+}
+
+int main() {
+  int n;
+  printf(" n: ");
+  scanf("%d", &n);
+
+  if (n < 1) {
+    printf("Error: n must be >= 1\n");
+  } else {
+    printf("Sum 1..%d = %d\n", n, sum_to_n(n));
+  }
+
+  return 0;
+}