import math m,t,s=map(eval,input().split()) if t!=0 and s%t!=0 and mt>=s: x=s/t x=math.ceil(x) sheng=m-x elif t!=0 and s%t==0 and mt>=s: x=s/t sheng=m-x elif t!=0 and s>m*t: sheng=0 else: sheng=0 print(f'{sheng}')