#include <stdlib.h>
main()
{
char str[80];
int i;
printf("input a string:\n");
scanf("%s",str);
for (i=0;i<strlen(str);i++){
if (str[i]>='a' && str[i] <='z') {
str[i]=str[i]+2;
if (str[i]>'z')str[i]=str[i]-'z'+'a'-1;
} else if (str[i]>='A' && str[i] <='Z') {
str[i]=str[i]+2;
if (str[i]>'Z')str[i]=str[i]-'Z'+'A'-1;
};
}
printf("%s\n",str);
}