diff --git a/du1/program.c b/du1/program.c
index 26fe26f..c2a7bab 100644
--- a/du1/program.c
+++ b/du1/program.c
@@ -22,10 +22,10 @@ int main() {
         return 0;
     }
     assert(r != NULL);
-    char *px = line;
-    while (isspace((unsigned char)*px)) px++;
-    x = strtod(px, &endptr);
-    if (px == endptr) {
+    x = strtod(line, &endptr);
+    char *p_check = line;
+    while (isspace((unsigned char)*p_check)) p_check++;
+    if (p_check == endptr) {
         return 0;
     }
     while (fgets(line, LINE_SIZE, stdin) != NULL) {