a, b, c = map(int, input().split())

def is_ok(x):
    z = x//a
    y = z*b+(x-z)*1
    if y >= c:
        return True
    else:
        return False

ng = 0
ok = 10**18+1
while ng+1 < ok:
    mid = (ng+ok)//2
    if is_ok(mid):
        ok = mid
    else:
        ng = mid
print(ok)