#include<iostream> using namespace std; int main(){ int money,y1,y2,y5,total=0; scanf("%d",&money); money=money*100; for(int i=1;i<=money/5-1;i++){ int left=money-5*i; if(i%2==1) total+=left/2; else total+=left/2-1; } printf("%d",total); return 0; }