diff --git a/README.md b/README.md
index b218723..13222a9 100644
--- a/README.md
+++ b/README.md
@@ -22,15 +22,16 @@ cmake --build build
 ```
 $ cmake -Bbuild -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_CXX_FLAGS="-march=native -mtune=native"
 $ cmake --build build
-`
+```
 
 # Usage
 
-`./swsf_bruteforce -s [START_LENGTH] -l [LENGTH] -e 0xABCDABCD`
+`./swsf_bruteforce [-X] -s [START_LENGTH] -e [LENGTH] 0xABCDABCD`
 
 where:
 
-`-s [START_LENGTH]` is the guessed start bound (greater than 2, less than end bound)
-`-l [LENGTH]` is the guessed end bound (less than or equal to 8)
+`-X` enables exact length, the value of -s is used and only that length is checked.
+`-s [START_LENGTH]` is the guessed start bound (greater than 2, less than the value of `-e`)
+`-l [END_LENGTH]` is the guessed end bound (greater than the value of `-s`, less than or equal to 8)
 `0xABCDABCD` is the hash to use