#include<stdio.h>   

int main(){ 
	int i,sum=0;

	for(i = 100;i >= 1;i-=3){ 
		sum += i;   
	}
	
	printf("%d",sum);
	return 0;
} 
/**************************************************************
	Problem: 1053
	User: admin
	Language: C
	Result: Accepted
	Time:6 ms
	Memory:1036 kb
****************************************************************/