I got Wrong Answer #1 what is it?

#include <stdio.h>
main(){
 unsigned long t[100],s[100];
 int ct,cs,c,c2,a;
 a=0;
 scanf("%i",&ct);

 for(c=0;c<ct;c++){
  t[c]=0;
  scanf("%ld",&t[c]);
 }

 scanf("%i",&cs);

 for(c2=0;c2<cs;c2++){
 s[c2]=0;
  scanf("%ld",&s[c2]);
 }

 for(c=0;c<cs;c++){
  for(c2=0;c2<ct;c2++){
   if(t[c2]==s[c]){ a++; }
  }
 }
 printf("%i",a);
 return 0;
}



in C language.

The limit is too small you shuold put unsigned long