int dp[26][1501];

void solve(int tc) {
	memset(dp, -1, sizeof(dp));
	int N, Q;
	string S;
	cin >> N >> S >> Q;
	while(Q--) {
		int amount; cin >> amount;
		int storeAmount = amount;
		char C; cin >> C;
		if(dp[C - 'a'][amount] != -1) {
			cout << dp[C - 'a'][amount] << nl;
			continue;
		}
		int right = 0, left = 0;
		int mx = 0;
		while(right < N) {
			if(S[right] == C) {
				right++;
			}else if(S[right] != C && amount > 0) {
				right++;
				amount--;
			}else {
				if(S[left] != C) {
					amount++;
				}
				left++;
			}
			mx = max(mx, right - left);
		}
		cout << min(N, mx) << nl;
		dp[C - 'a'][storeAmount] = mx;
	}
}