diff --git a/day2/src/p1.c b/day2/src/p1.c
index f707f25..d9f5105 100644
--- a/day2/src/p1.c
+++ b/day2/src/p1.c
@@ -20,10 +20,12 @@ struct proc {
 #define _LIT_MV_UP "up"
 #define _LIT_MV_DOWN "down"
 
+_Static_assert(sizeof(_LIT_MV_FORWARD)==8, "bad literal size");
+
 static const struct proc MAP[255] = {
-	['f'] = { .mv = 8, .field = (offsetof(struct psum, forward) / sizeof(result_t)) },
-	['u'] = { .mv = 3, .field = (offsetof(struct psum, up) / sizeof(result_t)) },
-	['d'] = { .mv = 5, .field = (offsetof(struct psum, down) / sizeof(result_t)) },
+	['f'] = { .mv = sizeof(_LIT_MV_FORWARD), .field = (offsetof(struct psum, forward) / sizeof(result_t)) },
+	['u'] = { .mv = sizeof(_LIT_MV_UP), .field = (offsetof(struct psum, up) / sizeof(result_t)) },
+	['d'] = { .mv = sizeof(_LIT_MV_DOWN), .field = (offsetof(struct psum, down) / sizeof(result_t)) },
 };
 
 static const unsigned char DIGITS[255] = {