#include <stdio.h>

int main(void)
{
    long number = 1e9;

    // printf() displays the formatted output
    printf("Now summing up all numbers from 1 to %li...\n", number);

    // sum up from 1 to number
    long sum = 0;
    for (long i = 1; i <= number; i++) {
      sum += i;
    }

    printf("Sum = %li\n", sum);
    
    return 0;
}