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

#define N 2e6

int main(void)
{
    char *s = calloc(N+1, sizeof(char));
    size_t p=2, i;
    unsigned long long sum=0;

    while (p*p < N) {
        for (i=p*p; i<=N; i+=p) s[i] = 1;
        while (s[++p]);
    }

    for (i=2; i<N; ++i)
        if (s[i]==0) sum+=i;

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

    return 0;
}