Hello.

I don't know what is wrong with my solution, maybe someone can help me.
here is my code


#include <stdio.h>

int maxdivisor(unsigned long long n)
{
    for(int i=9;i>1;i--)
        if(n%i==0)
            return i;
    return 1;
}

int main()
{
    unsigned long long n;
    scanf("%Ld",&n);
    if(n==0)
    {
        printf("10");
        return 0;
    }
    if(n<10)
    {
        printf("%Ld",n);
        return 0;
    }
    int dig[100];
    int k=0;
    int d;
    int flag=0;
    while(n>1)
    {
        d=maxdivisor(n);
        if(d==1)
        {
            flag=1;
            n=1;
        }
        else
        {
            dig[k]=d;
            k++;
            n=n/d;
        }
    }
    if(flag==1)
        printf("-1.");
    else
        for(int i=k-1;i>=0;i--)
            printf("%d",dig[i]);
    return 0;
}


Thanks in advance