diff --git a/src/cell.rs b/src/cell.rs
index 46fc530..3a14a5b 100644
--- a/src/cell.rs
+++ b/src/cell.rs
@@ -41,7 +41,7 @@ pub fn display_grid(grid: &Vec<Vec<Cell>>) {
             let y = j as usize;
             let state = grid[x][y].state as usize;
 
-            let index = map_num(state, 0, Q, 0, BRIGHTNESS.len());
+            let index = map_num(state, 0, Q as usize, 0, BRIGHTNESS.len());
             print!("{}", BRIGHTNESS.chars().nth(index).unwrap());
         }
         println!();