#include<bits/stdc++.h> 
using namespace std;
int main(){
	int s=100,n=0;
	while(s>=1){
	  n=s+n;
	  s=s-3;
	} cout<<n;
	return 0;
}
/**************************************************************
	Problem: 1053
	User: zhangchenhao
	Language: C++
	Result: Accepted
	Time:3 ms
	Memory:2072 kb
****************************************************************/