diff --git a/RPi/i2c_challenge.c b/RPi/i2c_challenge.c
index 094f272..381103d 100644
--- a/RPi/i2c_challenge.c
+++ b/RPi/i2c_challenge.c
@@ -44,7 +44,7 @@ int main(int argc, char *argv[]) {
 
   challenge = wiringPiI2CRead(fd);
   response = solve_challenge(challenge);
-  wiringPiI2CWrite(response);
+  wiringPiI2CWrite(fd, response);
 
   return 0;
 }