#include <vector>
#include <map>
#include<algorithm>
#include<cmath>
#include<set>
#include<cstdio>
#include <sstream>
#include <string>
#include<iostream>
#include<iomanip>
#include<stack>
#include<utility>
#include<unordered_map>
#include<queue>
#include<cstring>
#include <list>
#include<deque>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
unordered_map<string, int >var;
unordered_map<string, map<int, int>>isassigened;
int eval(const string &s)
{
	if (s.find("[") == -1)
	{
		int value= (int)stoi(s);
		return value;
	}
	string variable = s.substr(0, s.find("["));
	string subs = s.substr(s.find("[") + 1, s.rfind("]") - s.find("[") - 1);
	int ret = eval(subs);
	if (ret == -1 || var.find(variable) == var.end() || var[variable] <= ret || isassigened[variable].find(ret) == isassigened[variable].end())
		return -1;
	else
		return isassigened[variable][ret];
}
int main()
{
	//freopen("input.txt", "r", stdin);
	string statement;
	while (cin >> statement && statement != ".")
	{
		isassigened.clear();
		var.clear();
		int bugline = 0;
		bool bug = 0;
		do
		{
			if (bug == 0)
			{
				if (statement.find("=") == -1)
				{
					string name = statement.substr(0, statement.find("["));
					string s = statement.substr(statement.find("[") + 1, statement.find("]") - statement.find("[") - 1);
					int ints = (int)stoi(s);
					var[name] = ints;
				}
				else
				{
					int pos = statement.find("=");
					string left = statement.substr(0, pos);
					string left1=left.substr(left.find("[") + 1, left.rfind("]") - left.find("[") - 1);
					string right = statement.substr(pos+1, statement.size() - pos - 1);
					int leftret = eval(left1);
					int rightret = eval(right);
					if (leftret != -1 && rightret != -1)
					{
						string name = left.substr(0, left.find("["));
						if (leftret < var[name])
						{
							isassigened[name][leftret] = rightret;
						}
						else
							bug = 1;
					}
					else
						bug = 1;
				}
				++bugline;
			}
		} while (cin >> statement && statement != ".");
		if (bug == 0)
			cout << 0;
		else
			cout << bugline;
		cout << endl;
	}
	
}