Submission #1565034

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Source Code Expand

#include "iostream"
#include "climits"
#include "list"
#include "queue"
#include "stack"
#include "set"
#include "functional"
#include "algorithm"
#include "string"
#include "map"
#include "iomanip"
#include "random"

using namespace std;

const long long int MOD = 1000000007;
const long double EPS = 0.00000001;
const long double PI = 3.1415926535897932384626433;

long long int N, M, K, L, R, H, W;


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> N;
	for (int i = 0; i < N; i++) {
		string s;
		cin >> s;
		if (s[0] == 'A') {
			M++;
		}
		else {
			M--;
		}
		if (M < 0) {
			cout << "NO\n";
			return 0;
		}
	}
	if (M == 0) {
		cout << "YES\n";
	}
	else {
		cout << "NO\n";
	}
	return 0;
}

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