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