#include <stdio.h> int main() { int tian=0; int sum = 0; int k=1; scanf("%d", &tian); for (int i = 1; k <= tian; i++) { for (int j = 0; j < i; j++) { if(k>tian) break; sum+=i; k++; } } printf("%d", sum); return 0; }</stdio.h>