A, B, C = map(int, input().split())

def f(n): # n 歳の誕生日までにC円以上もらうか
    # 1 ~ n の間に A の倍数は何回あるか？
    cntA = n//A
    return cntA * B + (n - cntA) * 1 >= C

ok = 10**18
ng = 0
while abs(ok - ng) != 1:
    mid = (ok + ng)//2
    if f(mid):
        ok = mid
    else:
        ng = mid
print(ok)