#include <iostream>

using namespace std;

int main()
{
    int n,p,nr,M;
    cin>>n;
    M=0;
    p=1000000000;
    while(p>n)
        p=p/10;
    while(p>0){
        nr=(n/p/10)*p+n%p;
        if(nr>M)
            M=nr;
        p=p/10;
    }
    cout<<M;
    return 0;
}