#include <iostream>
#include <vector>
#include <cctype>
#include <cstring>
#include <sstream>

using namespace std;

string readString(){
   string line;
   getline(cin, line);
   return line;
}

void findMaxValue(vector<string> Vec){

    string currentString;
    string temp;
    int temporaryInteger = 0;
    int maxValue = INT_MIN;
    int len = Vec.size();
    for(int i = 0; i < len; ++i){
        currentString = Vec[i];
        int currentLen = currentString.size();
        for(int k = 0; k < currentLen; ++k){
            if(isdigit(currentString[k]) == true){
               temp += currentString[k];
            }
        }

        temporaryInteger = stoi(temp);
        if(temporaryInteger > maxValue){
            maxValue = temporaryInteger;
        }

        temporaryInteger = 0;
        temp = " ";
    }

     cout << maxValue;

}


int main()
{
    string eachElement;
    string inputData;
    vector<string> input;
    inputData = readString();
    istringstream istr(inputData);

    while(istr >> eachElement){
        input.push_back(eachElement);
    }

       findMaxValue(input);


    return 0;
}