I’m working on cs50 and I’m getting this error when trying to run. The program asks the user for a credit card number and then reports (via printf) whether it is a valid American Express, MasterCard, or Visa card number, using luhns algorithm and the requirements for each card. source code is below

#include <stdio.h>
#include <cs50.h>

bool validation(long number) {
    int i = 10;
    int j = 1;
    int totalMultiplied = 0;
    int totalNotMultiplied = 0;

    while (number / i != 0){
        totalMultiplied += ((number / i) % 10) * 2;
        i *= 100;
    }
    while (number / j != 0) {
        totalNotMultiplied += (number / j) % 10;
        j *= 100;
    }

    if ((totalMultiplied + totalNotMultiplied) % 10 == 0) {
        return true;
    }else {
        return false;
    }
}

int main(void) {
    long creditCardNo;
    do {
        creditCardNo = get_long("Enter credit card number: ");
    }
    while (creditCardNo < 0);

    int count = 0;
    long startNumbers = creditCardNo;
    long n = creditCardNo;

    do {
        n /= 10;
        count++;
    }
    while (n != 0);

    while (startNumbers >= 100) {
        startNumbers /= 10;
    }

    if (validation(creditCardNo)) {
        if (count == 15 && ( startNumbers == 34 || startNumbers == 35)) {
            printf("AMEXn");
        }
        else if (count == 16 && ( startNumbers == 51 || startNumbers == 52 || startNumbers == 53 || startNumbers == 54 || startNumbers == 55)) {
            printf("MASTERCARDn");
        }
        else if ((count == 13 || count == 14) && ( startNumbers / 10 == 4)) {
            printf("VISAn");
        }
    }else {
        printf("INVALIDn");
    }


}

I expected the program to print what type of card it was if the card was valid or invalid if the card was invalid