#include<stdio.h>

int main()
{
    int f = 0;
    char s[101];
    scanf("%[a-z ]s",s);
    for (int i = 0;;) {
        if(s[i] == NULL) break;
        if((s[i] == ' ' && i%2 == 0) || (s[i] != ' ' && i%2 == 1)) f = 1;
        i++;
    }
    f ? puts("No") :puts("Yes");
}