#include<bits/stdc++.h> using namespace std; using ll=long long; #define rep2(i, a, n) for(int i = (a); i < (n); i++) #define rep(i, n) rep2(i,0,n) int main(){ cin.tie(nullptr);ios_base::sync_with_stdio(false); string s; //$BA4$F$N4q?tHVL\$NJ8;z$,1Q>.J8;z$G!"A4$F$N6v?tHVL\$NJ8;z$,H>3Q%9%Z!<%9(B getline(cin,s); bool flag=true; for(int i=0;s[i]!='\n';i++){ //cout<<i<<" "<<s[i]<<endl; if(i%2==0&&!(s[i]>='a'&&s[i]<='z')){ flag=false; break; } if(i%2==1&&s[i]!=' '){ flag=false; break; } } cout<<(flag?"Yes":"No")<<endl; }