# oj t -c "python3 main.py"
import sys,math
from collections import defaultdict,deque
from itertools import combinations,permutations,accumulate,product
from bisect import bisect,bisect_left,bisect_right
from heapq import heappop,heappush,heapify
#from sortedcontainers import SortedList,SortedSet
def input(): return sys.stdin.readline().rstrip()
def ii(): return int(input())
def ms(): return map(int, input().split())
def li(): return list(map(int,input().split()))
inf = pow(10,18)
#////////////////////////////////////
A,B,X = ms()
ans = 0
cnt = 0
while cnt<X:
  ans += B
  cnt += A
print(ans)