#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ /* int n; char s1[100],s2[100]; cin>>s1; cin>>s2; cin>>n; strcat(s1,s2); cout<<s1[n-1]; */ /* char s1[1000],s2[1000]; cin>>s1; cin>>s2; int a=strcmp(s1,s2); if(a==0){ cout<<"yes"; }else{ cout<<"no"; } */ char s1[11]; cin>>s1; char max=s1[0]; int a=strlen(s1); for(int i=1;i<a;i++){ if(s1[i]>max){ max=s1[i]; } } cout<<max; return 0; }