C语言50分求助大佬

#include <stdio.h>
long long jc(long long x);

int main (void) {
    long long n;
    unsigned long long s=0;
    scanf("%lld", &n);
    for (int i = 1; i < n + 1; i++)
        s += jc(i);
    printf("%llu", s);

    return 0;
}

long long jc(long long x) {
    long long a = 1;
    for (long long j = 1; j <= x; j++)
        a *= j;

    return a;
}