#include <stdio.h>

int main(void){
    char c; bool f = false;
    while((c = getchar()) != '\n' and c != '\0'){
        f = not f;
        if(f){ if('a' <= c and c <= 'z') continue;}
        else if(c == ' ') continue;
        puts("No"); return 0;
    }
    puts("Yes");
    return 0;
}