#include <stdio.h>

int main(void)
{
  int N;
  int x, sum;

  scanf("%d", &N);
  printf("N = %d\n", N);
  
  sum = 0;
  for ( x = 1; x <= N; x++ ){
    sum += x;
  }

  printf("1 + ... + %d = %d\n", N, sum);

  return 0;
}