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
    else:
        t = 10**8
        if v-w > t and snr > t:
            for thr in [10**x for x in range(8,2,-1)]:
                if v-w > thr and snr > thr:
                    w += thr; s+= thr; snr -= thr
print(s)