#include <stdio.h>
#include <stdlib.h>

int main(void) {
    FILE *file1 = fopen("input.bin", "rb");
    if (!file1) {
        perror("Error opening input.bin");
        return 1;
    }

    int n;
    if (fread(&n, sizeof(n), 1, file1) != 1) {
        perror("Error reading input.bin");
        fclose(file1);
        return 1;
    }
    fclose(file1);

    printf("Got: %d\n", n);

    // Primes or smth
int count = 0;

    for (int i = 2; i < 500000; i++) {
        int prime = 1;
        for (int d = 2; d * d <= n; d++) {
            if (n % d == 0) {
                prime = 0;
                break;
            }
        }
        count += prime;
        n += 2;
    }

    FILE *file2 = fopen("output.bin", "wb");
    if (!file2) {
        perror("Error opening output.bin");
        return 1;
    }

    fwrite(&count, sizeof(count), 1, file2);
    fclose(file2);

    return 0;
}