这段代码运行后 应该输入什么啊！？求解！
#include<stdio.h>
char flag[30];
char ciphertext[30];
void change(char *flag)
{ int i;
for (i = 0; i < strlen(flag) ;i++)
flag[i] = (char)((int)flag[i] + 3);}
int main()
{ printf("I believe it is simple for you.\n"); printf("input flag:");
scanf("%s", flag);
if (strlen(flag) != 21)
{ printf("Ohhh,your flag is wrong!");
return 0; }
strcat(flag, "chenze");
change(flag);
strcpy(ciphertext, "iodj~Wk4vb4vbu6y6uv6€fkhq}h");
if (!strcmp(flag,ciphertext)) printf("Ohhhh,you are great!"); else printf("Ohhh,your flag is wrong!"); return 0;