#define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #define ll long long #define dou(s) atof(s.c_str()) #define lon(s) atoll(s.c_str()) #define str(n) to_string(n) #define rep(i,a,b) for(ll i=a;i=a;i--) #define ALL(a) a.begin(),a.end() #define fion(n) fixed<=n&&a[lower_bound(ALL(a),n)-a.begin()]==n?lower_bound(ALL(a),n)-a.begin():-1) #define fist(s,t) ((int)s.find(t)) #define START int main(){cin.tie(0);ios::sync_with_stdio(false); #define END } using namespace std; START string s;cin>>s; sort(ALL(s)); ll c=0; char k; rep(i,1,s.size()){ if(s[i-1]==s[i])i++; else{ c++; k=s[i-1]; } } if(c==1)cout<