l, r, c = map(int, input().split())

a = c%1000
min_cost = []
for i in range(1, 1001):
    x =  1000 - i * a
    if x >= 0:
        min_cost.append(x)
    else:
        min_cost.append(2000 - i * a)

if r - l < 1000:
    l = l%1000
    r = r%1000
    print(min(min_cost[l-1: r]))
else:
    print(min(min_cost))