let s = readLine()!
var u = 0
var c = 0
for i in s{
    if c % 2 == 1{
        if i != " "{
            u = 1
        }
    }else{
        if !i.isLowercase{
            u = 1
        }
    }
    c += 1
}
print(u == 0 ? "Yes" : "No")