diff --git a/ex21.c b/ex21.c
index cf032cb..767bf2f 100644
--- a/ex21.c
+++ b/ex21.c
@@ -29,5 +29,19 @@ int main(int argc, char *argv[])
     printf("INT64_MIN = %d\n", INT64_MIN);
 #endif
 
+    printf("sizeof(int_least8_t) = %d\n", sizeof(int_least8_t));
+    printf("sizeof(int_least16_t) = %d\n", sizeof(int_least16_t));
+    printf("sizeof(int_least32_t) = %d\n", sizeof(int_least32_t));
+#if defined(_M_X64) || defined(__amd64__)
+    printf("sizeof(int_least64_t) = %d\n", sizeof(int_least64_t));
+#endif
+
+    printf("sizeof(uint_least8_t) = %d\n", sizeof(uint_least8_t));
+    printf("sizeof(uint_least16_t) = %d\n", sizeof(uint_least16_t));
+    printf("sizeof(uint_least32_t) = %d\n", sizeof(uint_least32_t));
+#if defined(_M_X64) || defined(__amd64__)
+    printf("sizeof(uint_least64_t) = %d\n", sizeof(uint_least64_t));
+#endif
+
     return 0;
 }