#include <bits/stdc++.h>

using namespace std;

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    string s;

    cin >> s;

    if(s[0]-'0' + s[2] - '0' == s[1] - '0')
    {
        cout << "Yes" << '\n';
    }
    else
    {
        cout << "No" << '\n';
    }
    return 0;
}