a = input().split(' ')
m = int(a[0])
t = int(a[1])
s = int(a[2])

if m == 0:
    print(0)
if s/t != s//t:
    b = m - ((s//t)+1)
    print(b)
if s/t == s//t:
    c = m - (s//t)
    print(c)