a,b,c = map(int,input().split())
ans = set([])
if(c % a == 0):
    ans.add(c // a)
if((c + b) % a == 0):
    ans.add((c + b) // a)
    
if not(ans):
    print(-1)
    exit(0)
for k in sorted(ans):
    x = k * a
    if(x - b > 0):
        x -= b
    if(x != c):
        continue
    print(k)