diff --git a/2021/day7/7a.py b/2021/day7/7.py
similarity index 56%
rename from 2021/day7/7a.py
rename to 2021/day7/7.py
index e7dc9aa..843ee20 100644
--- a/2021/day7/7a.py
+++ b/2021/day7/7.py
@@ -1,13 +1,15 @@
 positions = [int(i) for i in open("input.txt", 'r').read().split(",")]
 
 width = max(positions)
-bestFuel = len(positions)*width
+part = input("a or b? ")
+bestFuel = len(positions)*width if part == "a" else len(positions)* int(((width ** 2 + width) / 2))
 bestPos = 0
 
 for i in range(bestFuel):
 	fuelUsed = 0
 	for pos in positions:
-		fuelUsed += abs(i - pos)
+		mov = abs(i - pos)
+		fuelUsed += mov if part == "a" else int(((mov ** 2 + mov) / 2))
 	if fuelUsed > bestFuel:
 		break
 	bestFuel = fuelUsed