#include <iostream>
#include <cstring>
using namespace std;


int main()
{
    char s[101],*p,cmax=' ',nmax[11];
    cin.getline(s,101);
    p=strtok(s," ");
    while(p)
    {
        if(p[0]>='0' && p[0]<='9')
            if(p[0]>cmax)
            {
                cmax=p[0];
                strcpy(nmax,p);
            }
        p=strtok(NULL," ");
    }
    if(cmax==' ') cout<<"nu exista";
    else cout<<nmax;
    return 0;
}