m, n, h = map(int,input().split());
d = 1
s = 0
while s <= h:
    s = d*(m-n) 
    if s < (h-m):
        d += 1
    elif s >= (h-m):
        print(d+1) 
        break;
 
/**************************************************************
	Problem: 1074
	User: admin
	Language: Python
	Result: Accepted
	Time:100 ms
	Memory:34480 kb
****************************************************************/