#include <stdio.h>

#define LENGTH 2000000

void main() {
    long long sum = 0;
    int numbers[LENGTH + 1] = {1};
    int i, j;

    for(i = 3; i < LENGTH; i = i + 2) {
        if(numbers[i] == 0) {
            continue;
        }

        if(isPrime(i) == 1) {
            for(j = 1; i * j < LENGTH; j++) {
                numbers[i * j] = 0;
            }
        }
    }

    for(i = 1; i < LENGTH; i++) {
        if(numbers[i] == 1) {
            sum += i;
        }
    }

    printf("SUM: %lld", sum);
}

int isPrime(int number) {
    int i;
    for(i = 3; i * i <= number; i = i + 2) {
        if(number % i == 0 && i != number) {
            return 0;
        }
    }

    return 1;
}