#include<bits/stdc++.h>
using namespace std;
int main(){
	freopen("add.in", "r", stdin);
	freopen("add.out", "w", stdout);
	long long h,d,n,l=1;
	cin>>h>>d>>n;
	n-=h;
  if(n%d==0) l=0;
	n/=d;
	cout<<n+l;
  return 0;
}