#include "bits/stdc++.h" using namespace std; #ifdef _DEBUG #define _GLIBCXX_DEBUG #include "dump.hpp" #else #define dump(...) #endif #define int long long #define ll long long #define DBG 1 #define rep(i, a, b) for (int i = (a); i < (b); i++) #define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--) #define loop(n) rep(loop, (0), (n)) #define all(c) begin(c), end(c) const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f; const int MOD = (int)(1e9) + 7; #define fi first #define se second #define pb push_back #define eb emplace_back using pii = pair; // template ostream &operator<<(ostream &os,T &t){dump(t);return os;} template istream &operator>>(istream &is, pair &p) { is >> p.first >> p.second; return is; } //template ostream &operator<<(ostream &os, pair &p) {os << p.first << " " << p.second;return os;} template void printvv(const vector> &v) { cerr << endl; rep(i, 0, v.size()) rep(j, 0, v[i].size()) { if (typeid(v[i][j]).name() == typeid(INF).name() and v[i][j] == INF) { cerr << "INF"; } else cerr << v[i][j]; cerr << (j == v[i].size() - 1 ? '\n' : ' '); } cerr << endl; } #ifndef _DEBUG #define printvv(...) #endif void YES(bool f) { cout << (f ? "YES" : "NO") << endl; } void Yes(bool f) { cout << (f ? "Yes" : "No") << endl; } template bool chmin(T& a, U b) { if (a > b) { a = b; return true; }return false; } template bool chmax(T& a, U b) { if (a < b) { a = b; return true; }return false; } signed main(signed argc, char *argv[]) { cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(12); string s; getline(cin, s); cin.ignore(); bool f = true; for (int i = 0; i < s.size(); i += 2) { if (s[i] == ' ')f = false; } for (int i = 1; i < s.size(); i += 2) { if (s[i] != ' ')f = false; } Yes(f); return 0; }