#include <fstream>
#include <cstdlib>

using namespace std;

int main() {
    ifstream fin("INPUT.TXT");
    ofstream fout("OUTPUT.TXT");
    
    char start[10], end[10];
    fin >> start >> end;
    fin.close();
    
    int start_col = start[0] - 'a';
    int start_row = start[1] - '1';
    
    int end_col = end[0] - 'a';
    int end_row = end[1] - '1';
    
    int can_reach = 0;
    
    if (end_row > start_row) {
        int diff_row = end_row - start_row;
        int diff_col = end_col - start_col;
        if (diff_col < 0) diff_col = -diff_col;
        
        if (diff_row == diff_col) {
            can_reach = 1;
        }
    }
    
    if (can_reach) {
        fout << "YES\n";
    } else {
        fout << "NO\n";
    }
    
    fout.close();
    
    return 0;
}