#include<bits/stdc++.h>
using namespace std;
int main(){double a,b,c,d,e,t1,t2,s1,s2;int n,num=0;//定义cin>>a>>b>>c>>d>>e>>n;//输入t1=sqrt(((a-e)*2.0)/10.0);t2=sqrt((a*2.0)/10.0);s1=b+d-t1*c+0.0001;s2=b-t2*c-0.0001;//小球位置是0到n-1for(int i=0;i<n;i++){if(i>=s2&&i<=s1)num++;}cout<<num;n-1//输出return 0;
}