v,t,p = map(int,input().split())

s,w,snr = 0,0,0
while w < v:
    w += 1; s += 1
    snr = snr-1 if snr>0 else snr
    if w==v and p>0:
        p -= 1
        w = 0
    elif snr==0:
        snr = t 
        w -= 1

print(s)