#include <stdio.h>
#include <math.h>

// The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.

// Find the sum of all the primes below two million.

int main() {
    unsigned long long sum = 0;

    int i = 2;

    while(i < 2000000) {
        if(isPrime(i) == 1) {
            sum += i;
        }

        printf("\n%d: %d", i, sum);

        if(i == 2) {
            i = 3;
        } else {
            i = i + 2;
        }
    }

    printf("\n\n%d", sum);

    return 1;
}

int isPrime(int number) {
    int i;
    for(i = 2; i < (int)sqrt(number); i++) {
        if(number % i == 0 && i != number) {
            return 0;
        }
    }

    return 1;
}