#include <iostream>
#include <string>
using namespace std;
int main()
{
string a;
while(getline(cin, a)){
for ( int i = 0 ; i < a.length() ; i++){
char ch;
ch = a[i]-7;
cout << ch;
}
a.clear();
cout << endl;
return 0;
#include
為什麼要加a.clear()?