#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
int Gets(char *buff,int buffMaxSize)
{
	buff[0]='\0';
	if (fgets(buff,buffMaxSize,stdin)==NULL){
		return -1;
	}
	size_t strLen = strlen(buff);
	if (strLen>0){
		while (buff[strLen-1] == '\r' || buff[strLen-1]=='\n'){//改行コード
			strLen--;
			buff[strLen]='\0';
		}
	}
	return (int)strLen;
}
int main(int argc, char* argv[])
{
	char S[101];
	Gets(S,100);
	size_t Len=strlen(S);
	for (int i=0;i<Len;i++){
		if (i%2==1){
			if (S[i]!=' '){
				cout<<"No"<<endl;
				return 0;
			}
		}else{
			if (S[i]==' '){
				cout<<"No"<<endl;
				return 0;
			}
		}
	}
	cout<<"Yes"<<endl;
	return 0;
}