x = [1, 5, 2, 4, 1]
k = 3
seen = set()
found = False

for num in x:
    if (num + k) in seen:
        print(f"Difference found: {num + k} - {num} = {k}")
        found = True
        
    seen.add(num)

if not found:
    print("No difference found")