#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)

template<typename T>
bool chmin(T &x, T y) { return x > y ? (x = y, true) : false; }
template<typename T>
bool chmax(T &x, T y) { return x < y ? (x = y, true) : false; }

struct io_setup {
	io_setup() {
		ios::sync_with_stdio(false);
		std::cin.tie(nullptr);
		cout << fixed << setprecision(15);
	}
} io_setup;

int main(){
	string a,b;
	cin>>a>>b;
	if(a.size()<b.size()){
		cout<<"No\n";
		return 0;
	}
	int m=b.size();
	rep(i,0,m){
		if(a.at(i)<b.at(i)){
			cout<<"No\n";
			return 0;
		}
	}
	cout<<"Yes\n";
}