测评记录

#include<bits/stdc++.h>
using namespace std;
char a[1200];
int b[27] ;
int main() {
	//freopen("x.in","r",stdin);
	//freopen("x.out","w",stdout);
	cin>>a;
	int len=strlen(a);
	for(int i=0;i<len;i++) b[a[i]-96]++;
	for(int i=1;i<26;i++){
		if(b[i]==1) 
		{
			cout<<(char)(i+'a'-1);
			return 0;
		}
	}
	cout<<"no";
	return 0;
}