#include <bits/stdc++.h>
using namespace std;
const long long inf = 4294967296;
int main() {
  int t, n, flag = 0;
  while (~scanf("%d", &t)) {
    char ch[10];
    long long loop = 1;
    long long ans = 0;
    stack<int> S;
    while (t--) {
      cin >> ch;
      if (ch[0] == 'a') {
        ans += loop;
        if (ans >= inf) flag = 1;
      } else if (ch[0] == 'f') {
        cin >> n;
        if (loop >= inf)
          S.push(1);
        else
          S.push(n), loop = loop * n;
      } else {
        if (!S.empty()) {
          int k = S.top();
          loop /= k;
          S.pop();
        }
      }
    }
    if (flag)
      cout << "OVERFLOW!!!" << endl;
    else
      cout << ans << endl;
  }
}
