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;
}