#include <iostream>
using namespace std;
int main()
{
    int c=0;
    for(int i=100;i>=0;i=i-3){
        c=c+i;
    }
    cout<<c;
    return 0;
}
/**************************************************************
	Problem: 1053
	User: wengzihang
	Language: C++
	Result: Accepted
	Time:4 ms
	Memory:2072 kb
****************************************************************/