<reponame>njw1204/BOJ-AC<filename>problem/01000~09999/01712/1712.py3.py
A,B,C=map(int,input().split())
if B>=C: print(-1)
else: print(A//(C-B)+1)
A,B,C=map(int,input().split())
if B>=C: print(-1)
else: print(A//(C-B)+1)