Tracks in Hackathon

Each person belongs to exactly one team, and each team has either a or b people. Split all p people into teams and find the minimum number of teams; output −1 if it is impossible.

输入格式

One line with a b p; full original bounds 1≤a,b,p≤100000.

输出格式

Output a single integer answer.

样例 1

输入：

3 4 7

输出：

2

样例 2

输入：

4 6 7

输出：

-1

样例 3

输入：

1 100 100

输出：

1

样例说明

The outputs of the three public examples are, in order: 2; -1; 1. These answers have been checked by independent enumeration or direct simulation.