poj1250 Tanning Salon

#include<stdio.h>
#include<string.h>
int main()
{
    char c,p[26];
    int n,curnum,leave;
    while(scanf("%d%*c",&n),n)
    {
        curnum=leave=0;
        memset(p,0,sizeof(p));
        for(c=getchar();c!='\n';c=getchar()){
            if(p[c-'A']==1){
                p[c-'A']=0;
                curnum--;
            }
            else if(p[c-'A']==0){
                if(curnum<n){
                    p[c-'A']=1;
                    curnum++;
                }
                else{
                    leave++;
                    p[c-'A']=2;
                }
            }
        }
        if(leave) printf("%d customer(s) walked away.\n",leave);
        else printf("All customers tanned successfully.\n");
    }
    return 0;
}