#include<bits/stdc++.h>
using namespace std;
int main(){
    int n=100,a=0;
    while(n>0){
    a=a+n;
    n=n-3;
}
    cout<<a;
    return 0;
}
/**************************************************************
	Problem: 1053
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:4 ms
	Memory:2072 kb
****************************************************************/