// editor
#include<iostream>
#include<string>
#include<cctype>
int main()
{
    char s[10050];
    if(fgets(s,sizeof(s),stdin)++NULL)
    {
        return 0;
    }
    int seen[26]={0};
    int i,count=0;
    for(i=0;s[i]!='\0';++i)
    {
        if(isalpha(unsigned char)s[i])
        {
            int idx=tolower ((unsigned char)s[i])-'a';
            if(!seen[idx])
            {
                seen[idx]=1;
                ++count;
                if(count==26)break;
            }
        }
    }
    if(count==26)
    {
        printf("YES\n");
    }
    else
    {
        printf("NO\n");
    }
    return 0;
}