#ngs
b1,b2,b3=(int(i) for i in input().split())
if b1==b2:
    b4=b1
else:
    r=b2-b1
    r1=b3-b2
    r1/=r
    r=r1*b1
    b4=b2-r
    b4+=r1*b3
ib4=int(b4)
if b4-ib4>0.999999:
    ib4+=1
print(ib4)